AHT 1170 Module A 2017 PDF - Olds College Pharmacy Terms

Summary

This Olds College AHT 1170 Module A 2017 document provides definitions and details regarding pharmacy terms, including the roles of veterinary technicians (RVTs), veterinary client-patient relationships (VCPRs), and key drug terminology. It also covers the identification of sources for various drugs, from plants and animals to synthetic and recombinant DNA technology.

Full Transcript

Module A1 Identify terms related to pharmacy. Source: Olds College, (2011). Pharmacy Terms As an RVT, you will need to be knowledgeable and competent in the l...

Module A1 Identify terms related to pharmacy. Source: Olds College, (2011). Pharmacy Terms As an RVT, you will need to be knowledgeable and competent in the language of pharmacy, as this comprises a significant part of most veterinary practices. Pharmacy is the branch of health sciences dealing with the preparation, dispensing, and proper utilization of drugs or a place where drugs are stored, compounded, or prepared for dispensing. In defining the terms related to pharmacy, you will: define the role of a RVT and a veterinary client patient relationship (VCPR) regarding drugs, define key drug terminology, and identify sources of drugs. OLDS COLLEGE AHT 1170 A-1  Define the role of a Role of a RVT and VCPR RVT and a VCPR Why does an RVT need to have a thorough knowledge of regarding drugs. pharmacy? Define key drug terminology. 1. Drugs are widely used in veterinary medicine. Identify sources of drugs. 2. RVTs may have the responsibility of ordering drugs for the clinic. 3. RVTs may have the responsibility of organizing the drugs into the pharmacy system that best suits the clinic's needs. 4. The RVT may be responsible for the administration of drugs. To do this the RVT needs to know: The reasons why the drug is used (pharmacotherapeutics). What happens to the drug in the animal (pharmacokinetics). How the drugs work (pharmacodynamics). What the adverse effects are (toxicology). 5. The RVT may be responsible for dispensing drugs. Must be able to educate clients on the use, administration, toxicity, or withdrawal periods of drugs. A valid VCPR is required to prescribe or sell: - prescription drugs. It is very important that you understand what an RVT may and may not legally do with regards to pharmacy. An RVT may dispense a prescribed drug. Dispensing means to provide a drug pursuant to a prescription, written or verbal, from a veterinarian. Dispensing does not include the administration of the drug. An RVT may NOT prescribe a drug. Prescribing means to provide a written or verbal directive for the compounding or dispensing and administration of drugs, or for other medical services to a particular patient. OLDS COLLEGE AHT 1170 A-2 AVMA Guidelines for Establishing and Maintaining a VCPR 1. A vet's medical judgement must be based on the consequences to the general public or for other commonly recognized public concerns. 2. Vet must use reasonable care, skill, and knowledge to prepare and maintain medical records of all services rendered to describe findings diagnostic (Dx), and pharmaceutical (Rx). 3. Vet must use sound medical judgement based on: i) Direct examination of patient(s) in prescribing a drug or course of Rx. ii) If not directly examining the patient(s), the vet must possess current, accurate, detailed, and relevant information regarding the animal(s). 4. Before dispensing a drug or allowing it to be dispensed, the vet must ensure that a valid VCPR appropriate to that drug exists; a VCPR is not necessarily established or maintained through previous sales of drugs and/or services. 5. When a vet is providing services limited to specific aspects of herd care, the limit of that vet's role must be clearly explained, in writing, to the client at the outset of the VCPR. 6. Where two or more vets knowingly act to serve the same animal(s) of a mutual client, they must, with the consent of the client, share information so all vets involved may make medical judgements based on current, complete, and relevant information. OLDS COLLEGE AHT 1170 A-3 Define the role of a Key Drug Terminology RVT and a VCPR The following terminologies are key elements in comprehending regarding drugs. the concepts that are presented throughout this module.  Define key drug terminology. Pharmacy Identify sources of drugs. The branch of health sciences dealing with the preparation, dispensing, and proper utilization of drugs. Can also be the place where drugs are compounded or stored. Pharmacology The study of the effect of drugs on the structure and metabolism of tissue. Pharmacokinetics The action of drugs in the body including the absorption, distribution, metabolism, and excretion of the drug. Toxicology The study of the adverse effects of chemicals on tissues or bodies. Patent The legal right given by the government to a company that originated a new drug to have exclusive rights to manufacture that product for a certain length of time (usually a certain number of years) before any other company can manufacture generic equivalents. Withdrawal Period The amount of time that it takes for a drug to safely be eliminated from meat or milk after the use of that drug has been stopped. Chemical Name When a drug is first discovered, it is given a chemical name, which describes its molecular structure. Drug A substance used to diagnose, prevent, or treat disease. Generic Name When a drug is approved, a federal agency responsible for naming the drug gives it a generic (official name). OLDS COLLEGE AHT 1170 A-4 Trade Name or Brand Name This is the unique (exclusive) name that a pharmaceutical company chooses to give to the drug they are manufacturing. Example: Chemical Name 7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one Generic Name: Diazepam Trade Names: Valium, Novo-Dipam Example: Dexamethasone Chemical Name Prega – 1, 4 – Diene – 3, 20 Dione, 21 – (Acetyloxy) – 9 Fluro-11, 17 Dihydroxy – 16 – Methyl, (11 Beta, 16 Alpha) – Monohydrate Generic Name: Dexamethasone Brand names: Azium, Azimycin, Centrazone, Dexamone, Dexamycin, Dexone, Hostadex, Maxidex, etc. Unapproved drug A drug product that does not have a Drug Identification Number (DIN). A drug that has never been approved by a Canadian regulatory authority. Banned Drug Drugs banned by Health Canada from use in animals intended for use in human food. Compound The application of professional knowledge for the purpose of mixing two or more ingredients together; at least one ingredient must be a drug. Nutraceutical The combination of the words: nutrition and pharmaceutical. Refers to any substance that is isolated or purified from food and claims to provide a physiological benefit or protection against chronic disease. In Canada, nutraceuticals are not allowed to claim they “cure, treat, mitigate or prevent a condition” as drugs can claim. As they are not classed as drugs, they do not have a DIN and often do not have the rigorous, scientific evidence of research and trial to substantiate their health benefits. OLDS COLLEGE AHT 1170 A-5 Define the role of a Sources of Drugs RVT and a VCPR regarding drugs. Plants Define key drug terminology. Examples:  Identify sources of Herbs drugs. Atropine Digoxin Vitamins Animals Examples: Insulin Hormones Antibodies Minerals Examples: Electrolytes Mineral injections or oral supplements Bacteria/Molds Examples: Antibiotics Antifungals Anthelmintics Semi-Synthetic Semi-synthetic drugs are natural drugs that have been altered in a laboratory (additions, deletions). Examples: Amoxicillin Ampicillin Synthetic Man-made chemical synthesis. Examples: Sulfonamides OLDS COLLEGE AHT 1170 A-6 Recombinant DNA Technology Recombinant DNA technology involves identifying the genes from animals or humans that code for a desired protein product and then inserting these specific genes into easily manipulated, non-pathogenic cells such as bacteria, yeast cells, or plants. These genes then act as "manufacturing factories" that produce the desired protein in large amounts. The proteins are then purified and used therapeutically. Examples: Insulin Interferon Vaccines Human growth hormone Antibodies New technology is already being used to insert genes into animal embryos so that these mature animals will produce the desired proteins that the originally transferred genes coded for. OLDS COLLEGE AHT 1170 A-7 Abbreviations Used in Pharmacology #, no - number Oph - ophthalmic ad lib - as freely or as often as needed OS - lt eye am - morning Ot - otic ASAP - as soon as possible OTC - over the counter B&A - bright and alert OU - both eyes bid - every 12 hours (2 times a day) oz - ounce Bol - bolus per os, po - by mouth C - controlled drug pm - afternoon c - cup Pr - prescription required Cap - capsule ppm - parts per million cc - cubic centimeter prn - as necessary, when required d - day pwd - powder DIN - drug identification number q - every Dx - diagnosis q2d - every 2 days EOD - every other day qd - once daily, every 24 hours fl - fluid qh - every hour gal - gallon q2h - every 2 hours gm, g - gram qid - every six hours (4 times a day) GU - genitourinary qt - quart h, hr - hour ® - registered trademark H 2O - water Rx - prescribe, prescription or "take Hx - history thou" IM - intramuscular SC, SQ, Subq - subcutaneous IN - intranasal Sig - write directions for client IP - intraperitoneal sid - once per day (every 24 hours)* IU - international units or SR - sustained release intrauterine Sx - surgery IV - intravenous stat - immediately kg - kilogram T, tbsp - tablespoon L - liter t, tsp - teaspoon L.A. - long acting Tab - tablet MEq - milliequivalent tid - every 8 hours (3 times per day) mcg, ug - microgram Tx - treatment mg - milligram ug - microgram, mcg ml - milliliter (same as a cc) V/V - volume in volume N - narcotic wk - week non rep, nr - no repeats wp, WD - withdrawal period NPO - nothing per os (per mouth) w/v - weight in volume OD - rt eye *NOTE: S.i.d. is strictly a veterinarian abbreviation and is unknown to most other health professionals including pharmacists. Source: Olds College, (2007). References Demo pharmacy [Photograph]. (2011). Olds, AB. Olds College. Abbreviations [Figure]. (2007). Olds, AB. Olds College. OLDS COLLEGE AHT 1170 A-8 Module A2 Describe the forms of drugs and their routes of administration. Source: Olds College, (2012). Drug Forms/Administration Since, as an RVT, you may be ordering drugs, using drugs on veterinary patients, or dispensing products to clients under a veterinarian's order, you will need to know in what forms drugs are available. You also need to understand the advantages and disadvantages of the various routes that may be used for administration of a particular product. In describing the forms of drugs and routes of administration, you will: describe the physical states of drugs, and explain the advantages or disadvantages of the various routes of administration. OLDS COLLEGE AHT 1170 A-9 Physical State of Drugs  Describe the physical states of drugs. Drugs may be grouped according to their physical state: Explain the advantages or disadvantages of the various 1. Liquids routes of administration. 2. Semi-solids 3. Solids 4. Gases Drug Forms Drugs are designed for convenient administration. Drugs may be available in more than one form. Examples: Baytril (liquid, injectable, and tablets). Ivermectin (oral drench or paste, injection form, pour-on, dry pre-mix, slow release bolus, flavoured tablets). Liquids Solution A mixture where the solute is completely dissolved in the solvent (solute is the dissolved substance and a solvent is the dissolving substance). They do not settle out (precipitate). Examples: Dexamethasone solution. A tincture is a specific type of solution in which the solvent is alcohol. Examples: Tincture of iodine. Suspensions A mixture where the solute particles are large and suspended, but not dissolved in the solvent. The solute will settle out, so should be shaken well prior to use. Lotions Lotions are used for external (topical) or mucus membrane application. They are meant to be a soothing product. OLDS COLLEGE AHT 1170 A-10 Examples: Calamine lotion. White lotion. Liniment A topical application to counter irritation (a superficial irritation to relieve pain deeper). Liniments can feel warm or cool on the skin depending on whether alcohol is part of the mixture. Examples: Myotensyn liniment (horses). Stericool gel liniment (horses). Drench Is an liquid administered orally. Examples: Ivomec drench. Dioctate anti-bloat drench. Syrups Contain the drug and a flavoring liquid for oral use. Examples: Ipecac syrup. Semi-Solids Ointments Are usually water in oil emulsions with oil being the greater component. They are not water-miscible. They are used for dry lesions. Examples: Panolog ointment. Otomax ointment. Creams Are oil in water, with water being the greater component. They are water-miscible and are used for moist lesions. OLDS COLLEGE AHT 1170 A-11 Examples: Panalog cream. Dermadex cream. Suppositories Are used for insertion into the vagina, uterus, or rectum. Examples: Gravol suppositories. Pastes A common form of oral medication. Examples: Tribrissen antibiotic paste. Butequine analgesic paste. Ivomec deworming paste. Gels Transparent or translucent. Examples: Quest oral deworming gel. Domoso topical anti-inflammatory gel. Solids Solids are the most popular form of oral medications. Tablet (Tab) or Caplet They are a firm, powder mixtures that are compressed, usually with a stabilizer, color, or lubricants. If scored, the tablet has an indentation to allow it to be broken apart easier. Examples: Amoxil antibiotic tablets. Rimadyl anti-inflammatory caplet. OLDS COLLEGE AHT 1170 A-12 Bolus (Bol) A large tablet. NOTE: Examples: Bolus can also be defined as: 1. Any concentrate given as Naquaone diuretic bolus. a single dose to achieve an immediate effect. Tribrissen scour bolus. 2. A large IV dose of a drug given all at once at the beginning Capsule (Cap) of treatment, which raises the concentration in the body to a A powder within a gelatin case. therapeutic level. Examples: Source: Segen, (2002). Amoxil antibiotic capsules. Glucosamine capsules. Implants (Imp) Hard pellets designed to be inserted subcutaneously (SQ). Example: Ralgro growth implants. Granules (Gran) Small balls of compressed powder. Example: Atravet tranquilizer granules. Powder (Pwr) The simplest form. Usually a mixture of the drug and a diluent. Examples: Butazone anti-inflammatory powder. Tetracycline antibiotic powder. Flea and tick powders. OLDS COLLEGE AHT 1170 A-13 Routes of Administration Describe the physical states of drugs. To be effective, drugs must be absorbed, transported to the  Explain the advantages or appropriate tissue or organ, penetrate to the subcellular level, disadvantages of the various routes of administration. and elicit a response or alter an ongoing process. The route by which a drug is administered depends on a number of factors, including the: Chemical and physical properties of the drug. Form the drug is available in. Condition for which the animal is being treated. Behavioral and/or physiological characteristics of the animal being treated. Oral This is a very common route via feed, water, drench, pastes, nasogastric tubes, pills, or boluses. They are absorbed relatively slowly. Absorption is affected by many factors (see section on pharmacokinetics in oral absorption of drugs in Module B1). Topically The drug is applied at the site where it is needed (e.g. on skin or other membranes). Alternatively, the drug can be absorbed from its application site and work systemically. Examples of topical applications include: Intramammary Ophthalmic Otic Rectal (suppositories) Intrauterine Vaginal Nasal Sublingual Skin OLDS COLLEGE AHT 1170 A-14 Parenterally The drug is given by injection and follows many routes. 1. Subcutaneous (SC, SQ) Slower absorption. Cannot be used to administer irritating or hyperosmotic drugs (e.g. Pentothal). Can be used to administer fluids (LRS, NaCl), but not those containing dextrose. Many drugs are given by this route (e.g. insulin, vaccines, some antibiotics). SQ injections of the ear are used for growth implants in cattle, but this is now a new area for antibiotic injection in cattle. 2. Intramuscular (IM) NOTE: Intramuscular injection is not Drug injected into the muscle. acceptable in hind quarters of food-producing animals any Usually a more rapid rate of absorption than SQ, but not more, because of the potential to as fast as IV. damage the meat in this higher value area of the carcass. Actual rate depends on the form, as it can be in a substance that delays absorption (e.g. Oxytetracycline LA). Common route for many drugs (vaccines, antibiotics, NSAIDs). Potential problems: - cannot be used for irritating substances (stings, muscle necrosis); - danger of IV administration; - danger of injecting close to nerves (temporary paralysis); - damage to carcass. Possible carcass damage: - abscesses; - drug residues; - scars; - broken needles; - toughness of surrounding meat fibers. OLDS COLLEGE AHT 1170 A-15 The site below has some additional information on administration routes. 1. Using Google, search: "Canadian Cattle Quality Starts Here" Choose CCA: Quality starts here. Choose Factsheets. Choose: Prevention of injection site lesions. http://www.cattle.ca/qsh/qsh/fact_sheets/Injection%20Site%20Scars.PDF 3. Intravenous (IV) Drug injected directly into a vein. Immediate drug availability. NOTE: Preferred route for large volumes of fluid (e.g. for Only drugs labeled for IV dehydrated animals). administration - not suspensions. Can give irritating drugs (e.g. Pentothal, Dextrose, Phenylbutazone). NOTE: Rate of injection important - rapid can induce toxic/ Make sure you never inject into an artery by mistake. allergic reaction. IV IM Plasma Drug Concentration SQ or Oral O Time Figure A2-1 The effect on plasma drug concentration by administration route. Source: Olds College, (2007). OLDS COLLEGE AHT 1170 A-16 4. Intra-articular (IA) Inject into a joint (e.g. local anesthetic, hyaluronic acid, corticosteroids). Absolute sterility a must. 5. Intra-peritoneal (IP) Injection into the abdominal cavity. Can be used for fluids or euthanasia solutions in pocket pets and small birds. 6. Intracardiac (IC) Euthanasia. Perhaps for cardiac resuscitation of dying animals. 7. Intradermal (ID) Allergy testing. TB testing. 8. Subconjunctival To treat certain eye conditions. Medication injected under the conjunctiva. 9. Intra-arterial Injection into an artery. Rarely used intentionally, but has been used with a tourniquet for injection of an antibiotic into an artery leading to an infected bone area. A potential hazard of jugular intravenous injections is the accidental administration of the drug into the carotid artery, resulting in seizures and/or death of the animal. 10. Intramedullary (Intraosseous) Injection into the marrow cavity of an infected bone (osteomyelitis). A hole is drilled through the cortex of the bone and the port of an IV extension set is seated into the hole so that a syringe can be attached and medication periodically instilled right where it is needed. This route can also be used as an emergency procedure to deliver blood and/or fluids to small, severely dehydrated animals. OLDS COLLEGE AHT 1170 A-17 11. Epidural Injection into the epidural space between caudal vertebrae. Usually for anesthetic purposes. 12. Inhalation Drugs in a gaseous form delivered to the patient in inspired air (e.g. anesthetics via masks or tracheal tubes or bronchodilators via inhalers such as Aero Kat). References Drug forms [Photograph]. (2012). Olds, AB. Olds College. Effect on plasma drug concentration [Figure]. (2007). Olds, AB. Olds College. Segen, J. C. (2002). Concise Dictionary of Modern Medicine. New York, NY: McGraw-Hill. OLDS COLLEGE AHT 1170 A-18 Module A3 Describe the processes of pharmacokinetics and pharmacodynamics. Source: Olds College, (2012). Pharmacokinetics & Pharmacodynamics Pharmacokinetics covers the complex events that occur after a drug is administered to patients. This topic will be covered in four general areas: absorption, distribution, metabolism, and excretion. It is important for anyone who has the responsibility of choosing, administering, and dispensing of drugs, monitoring patients, or advising clients to have a basic understanding of each of these four areas. This knowledge will help ensure that the proper drugs are chosen, the best route is used, and that side effects are watched for, so that the least amount of possible harm is caused and the greatest advantage for our veterinary patients under our care is provided. In describing the processes of pharmacokinetics, you will: explain absorption and the methods of absorption, describe factors that affect absorption, explain drug distribution, identify factors that affect the distribution rate of drugs, explain drug metabolism, describe routes for the elimination of drugs, explain the concept of drug half-life, and describe disease states that could affect drug excretion. OLDS COLLEGE AHT 1170 A-19 Pharmacokinetics Pharmacokinetics is the study of what happens to the drug(s) in the animal's body after it is administered. It covers absorption, distribution, metabolism, and excretion (ADME). ADME describes the disposition of a pharmaceutical compound within an organism. These four criteria all influence the drug levels and kinetics of drug exposure to the tissues; hence they influence the performance and pharmacological activity of the compound as a drug. (Scientists Against Malaria, n.d.).  Explain absorption and the Absorption methods of absorption. Absorption is the process by which a drug crosses Describe factors that affect absorption. various barriers to reach the bloodstream (i.e. Explain drug distribution. the movement of drug particles from the site of administration into the systemic circulation). Identify factors that affect the distribution rate of The only route where absorption is not a factor to be drugs. considered is the IV route, as the drug is placed directly Explain drug metabolism. into the systemic circulation. Describe routes for the elimination of drugs. Note the difference in meaning from adsorption (i.e. the Explain the concept of action of a substance in attracting and holding other drug half-life. materials or particles on its surface). Describe disease states No matter what form the drug is in or by what route it that could affect drug excretion. is administered, in order for it to have an effect, it must enter the body fluids. Bacteremias would be a situation where it would be beneficial to have an antibacterial drug stay in the bloodstream. Bioavailability is the degree to which a drug is absorbed and becomes available via the general circulation. Despite anatomical differences, the methods by which different drugs cross the various membrane barriers are the same. OLDS COLLEGE AHT 1170 A-20 There are two main methods of crossing cellular membranes: 1. Passive Processes NOTE: No energy expended by the cell: Most drugs cross membranes this way by passive process. i) Simple diffusion from an area of high concentration to an area of low concentration. ii) Water-soluble drugs cross membranes through pores or channels (facilitated diffusion). iii) Lipid (fat) soluble drugs cross cell membranes by dissolving in them. 2. Active Processes Requires energy to move substances against the concentration gradient (i.e. the substance is moved from an area of low concentration to an area of high concentration). i) Active Transport - drugs can be transported by this method, if close in structure to endogenous substrate. ii) Pinocytosis, Phagocytosis - less common mechanisms, - engulfing particles or droplets, and - immunoglobulins are received into neonate animals by this method. Besides the method of absorption, there are a number of other factors that affect drug absorption including the: Route of drug administration (including natural barriers within the body). Drug solubility (fat versus H2O). Size of the drug molecule. Ionization of the drug molecule. Formulation of the drug. Concentration of the drug. Blood supply to the absorptive area. OLDS COLLEGE AHT 1170 A-21 Explain absorption and the Factors Affecting Absorption methods of absorption.  Describe factors that affect A. Factors For Route of Administration absorption. 1. Factors Affecting Absorption of Oral Drugs Explain drug distribution. Identify factors that affect Absorption must first occur through the gastrointestinal mucosa. the distribution rate of drugs. Since absorption occurs along the entire length of the GIT, the Explain drug metabolism. absorptive area is large and has a rich blood supply. Describe routes for the Gut fill and the rate of pyloric emptying may delay elimination of drugs. transit of drugs into the lower intestinal tract where the Explain the concept of majority are absorbed. E.g. very coarse fibrous feeds drug half-life. move through the GIT slower. Describe disease states that could affect drug Some drugs may bind to gut contents, which may delay excretion. or prevent absorption. E.g. tetracyclines bind with Ca, Mg, and Fe. Low gastric pH may destroy or inactivate some drugs. The presence of gastrointestinal disease is an important factor in altering the absorption of drugs E.g. loss of intestinal villi or increased rate of emptying such as with scours. Ruminants present special problems: Large capacity of rumen dilutes drugs. pH 5.5–6.5 tends to cause ion trapping of basic drugs (more on this later). Microbial activity - affects the stability of many drugs. Rate of passage of feed out of the rumen depends on the amount of feed the ruminant is eating and the digestible level of the feed. 2. Factors Affecting Absorption of Parenteral Drugs Parenteral describes the injection route of administration (i.e. IM, SQ, IV, etc.). IV or IA routes eliminate the need to diffuse into the circulatory system. For IM, SC: - multiple injection sites increase absorption by increasing the absorptive surface area; - IM injections tend to be absorbed faster than SC, because of the increased blood flow to muscles compared to under the skin. OLDS COLLEGE AHT 1170 A-22 Parenteral drugs must be formulated to be: - pyrogen-free (i.e. not causing a fever); - sterile; - adjusted to body pH; - adjusted to body osmolality. 3. Factors Affecting Absorption of Topical Drugs Topical describes the route of administration where the drug is applied to various body surfaces (i.e. skin or various mucous membranes). Drugs are generally absorbed more slowly through the skin than through other body membranes. The sebaceous secretions of skin and the keratinized epithelium limit absorption to lipid-soluble molecules only. Therefore, topical medications are usually formulated in fats or fat solvents. Increased absorption occurs if the skin is broken. Also, increased circulation to the skin allows for increased absorption. The rate of absorption may be increased by placing the drug in a vehicle such as dimethyl sulfoxide (DMSO). 4. Factors Affecting Absorption of Inhaled Drugs Covered more specifically in the Anesthesia course, Generally, very rapid absorption due to large surface area with excellent blood supply. B. Absorption Affected by Drug Solubility Lipid-soluble (fat-soluble) drugs cross cell membranes more readily than water-soluble drugs; therefore, a highly lipid-soluble drug has enhanced absorption. The lipid solubility factor is important at all barrier membranes, except the final capillary endothelium before it reaches the target site. This is because the capillaries are only one cell thick and have gaps between these cells (i.e. large enough to allow drug molecules to move in and out easily). OLDS COLLEGE AHT 1170 A-23 Examples of solubilities of various common antibiotics: Water-soluble antibiotics (least easily absorbed): - penicillins - aminoglycosides - sulfinamides - B-lactams Intermediate fat-soluble antibiotics: - tetracyclines Fat-soluble antibiotics: - macrolides - fluoroquinolones C. Absorption Affected by Size of Drug Generally, the smaller the drug molecule, the easier it can be absorbed. Drug molecules with large molecular weight are excluded from endothelial pores and gain access to circulation via the lymphatics instead, so absorption is slowed. D. Absorption Rate Affected by Ionization State of Drug Non-ionized drugs (i.e. having neither a "+" or "-" charge) diffuse through cell membranes easier than drug molecules with a charge. Whether a drug molecule is ionized or not, depends on the pH of the drug and the pH of the solution in which the drug is dissolved. If a drug is acidic, it is ionized in a basic environment; therefore, it is not absorbed well. If a drug is basic, it is ionized in an acidic environment; therefore, it is not absorbed well. Most drugs are either weak acids or weak bases; therefore, they exist in both ionized and non-ionized forms in solution at body pH. Acid drugs are absorbed better in an acidic environment and basic drugs are absorbed better in basic environments. OLDS COLLEGE AHT 1170 A-24 Examples: Within the GIT, the stomach has an acidic pH, while the small intestine has a basic pH. If an animal is given an acidic drug (e.g. ASA), it will be mostly non-ionized in the gastric environment and will be absorbed quickly through the gastric mucosa. A basic drug would be mainly in the ionized form in the stomach, as it moved along into the basic environment of the small intestine it would become mainly non-ionized and be readily absorbed. Oral drugs Weak acid A or weak base B Stomach Acid pH = 2.0-3.0 B+H+ BH+ Most is in ionized form Basic drug is mostly ionized in ⇐ an acid environment so is NOT AH absorbed well A- + H + Most is in unionized form ⇐ Duodenum pH = 8 (basic) ⇐ B+H A-+H+ + BH + AH Most is in ionized form Most is in unionized form ⇐ Acid drug is mostly ionized in a basic environment, so is NOT absorbed well. Figure A3-1 Ionization effects on absorption. Source: Olds College, (2007). Examples of basic drugs: Aminoglycosides Macrolides Ketamine Piperazine Xylazine OLDS COLLEGE AHT 1170 A-25 Examples of acidic drugs: Tetracyclines Sulfonamides Cephalosporins Barbiturates Penicillin Examples of pH of various body sites: Rumen 5.5–6.5 Abomasum 3 Duodenum 8 Plasma 7.4 Carnivore urine 5.5–7.5 Ruminant urine 6.0–9.0 E. Absorption Affected by Formulation of Drug Many drugs are: 1. Combined with carriers or 2. Have protective coatings, which control the rate at which these preparations dissolve prior to being available for absorption (usually we try to prolong the absorption or try to control where the drug dissolves). Examples: Depo-Medrol Penlong XL Ivomec SR bolus Growth implants Buffered aspirin F. Absorption Rate Affected by Concentration of the Drug Generally the higher the drug concentration at a site, the faster the absorption, because of the larger difference in concentration gradients. OLDS COLLEGE AHT 1170 A-26 G. Absorption Rate Affected by Blood Supply to the Absorptive Area The greater the blood supply to the absorptive area, the faster the absorption. Skeletal muscle, liver, and kidney are examples of organs well perfused, which receive significant concentrations of drugs. Fat is relatively poorly perfused by blood circulation. The amount of movement in the injection area will enhance absorption. Massage and heat will also increase absorption by increasing blood flow to the area. Cooling and elevation of the area will decrease absorption. Poor circulation in the body (e.g. shock or cardiac failure) will decrease blood flow. Drug Distribution Explain absorption and the methods of absorption. Drug distribution includes all of the following: Describe factors that affect 1. The dispersion of drugs from their site of absorption to the absorption. site of their action.  Explain drug distribution. 2. A drug needs to get to its target cell to be effective, but Identify factors that affect the distribution rate of only a small amount of the drug given actually reaches the drugs. target cell receptor sites. Explain drug metabolism. 3. A drug moves from its absorption site into the plasma, Describe routes for the then from the plasma into the extracellular fluid (ECF), and elimination of drugs. finally into the cells. Explain the concept of drug half-life. 4. An equilibrium is established between the amount of drug in Describe disease states each of these compartments. that could affect drug excretion. 5. Equilibrium does not mean equal concentrations; the concentration of the drug within a particular compartment depends on many things (ionization, active transport, protein binding.) Administered Absorbed Distributed Action GUT MUCOSA PLASMA ENDOTHELIUM ECF CELL WALL TARGET CELL Protein bound Tissue bound ↓↑ ↓↑ Non-ionized → → → ↓↑ ← Non ionized ← Non ionized ← Site of Action Ions ↓↑ ↓↑ Ions ions Figure A3-2 Drug distribution. Source: Olds College, (2007). OLDS COLLEGE AHT 1170 A-27 Factors Affecting Drug Explain absorption and the methods of absorption. Distribution Describe factors that affect absorption. There are a number of factors that affect the distribution rate of drugs: Explain drug distribution.  Identify factors that affect Concentration gradient. the distribution rate of drugs. Protein binding. Explain drug metabolism. Storage in various tissues. Explain absorption and the Dilution in luminal fluids. methods of absorption. Describe routes for the Specialized barriers. elimination of drugs. Disease processes. Explain the concept of drug half-life. Describe disease states Factors That Affect Drug Distribution that could affect drug excretion. Some of these factors are the same factors that affect the absorption of drugs into the body. 1. Concentration Gradient Drugs tend to move from an area of high concentration to one of low concentration. 2. Protein Binding Drug in plasma is exposed to plasma proteins (albumin, globulins, glycoproteins). These proteins normally remain in the systemic circulation, because they are too large to pass through the capillary endothelial junctions (gaps). Some drugs may temporarily bind to these and become unable to leave the plasma compartment while bound; therefore, the drug is unable to exert its effect, be metabolized, or excreted (protein binding is like a storage depot). OLDS COLLEGE AHT 1170 A-28 Examples of drugs that tend to be highly protein bound: Corticosteroids. Digitoxin. Phenylbutazone. Lincomycin. Species vary in how much protein binding occurs with certain drugs. This may partially explain some of the species differences in dosage rates required for drugs. Plasma proteins can be lower in disease states (hypoproteinemia) or in young animals. Lower plasma proteins means decreased plasma binding and more drug can enter the ECF; therefore, a decrease in dose is required. 3. Storage in Various Tissues Once the drug has left the plasma compartment, it may be stored in tissue. It can be stored at the site of action or stored in other tissues especially fat, liver, kidney, and bone. If stored outside the site of action, it is unavailable to exert its effect while stored. Can cause prolonged effect as the drug is gradually released from storage (e.g. barbiturates). Example: Tetracyclines may bind to bone. Aminoglycosides may bind to renal tubular epithelium. Barbiturates may get stored in fat. Self Check A3-1 1. Would a fat patient be more likely to have a prolonged or a shortened duration of anesthesia than a leaner patient? 1. Prolonged Self Check Answers A3-1: OLDS COLLEGE AHT 1170 A-29 4. Dilution in Luminal Fluids Luminal fluids include: - rumen juice; - gut fluids; - body cavity fluids (e.g. peritoneal fluid); - joints. Drug may enter and become trapped in these; thereby, decreasing the blood concentration. Self Check A3-2 Remembering the ionization factor affecting binding of drugs, think about the following question: 1. Would an acidic environment be more likely to trap an acidic drug or a basic drug? 5. Specialized Barriers Certain tissues have barriers that retard not only the movement of all or certain classes of drugs into them, but also the distribution of these drugs once they have been absorbed into these sites. These sites include: Blood-Brain Barrier (BBB) Exists between plasma and the extracellular fluid of brain. Endothelial cells of capillaries have tight junctions instead of pores (gaps). Another reason for the BBB is that the glial cells around the capillaries create an additional physical barrier. Nutrients enter via carrier mediated systems (active transport). Lipid-soluble drugs diffuse through endothelial cells. Lipid-insoluble and highly ionized drugs enter very slowly. basic drug. When inflamed, the BBB may become more permeable 1. Acidic environment would trap a (allowing some antibiotics to enter). Neonatal animals have a less efficient BBB. Self Check Answers A3-2: OLDS COLLEGE AHT 1170 A-30 Placenta Not as effective a barrier as the BBB to many drugs (e.g. fetal effects from administered drugs). Lipid-soluble drugs diffuse across easily. Therefore, it is important in a C-section to choose a drug that does not cross as readily. Eye Tight capillary endothelium junctions limit absorption and distribution of drugs. Joint Synovia Poor absorption and distribution into the joints of animals suffering from infectious or inflammatory processes of their joints is frustrating. Again, this is probably because of the tight capillary endothelium junctions. Often we resort to a direct injection into the joint of antibiotics or anti-inflammatory drugs. 6. Disease Processes Antibiotics do not enter exudates, abscesses, or necrotic tissue very well due to the fibrous capsules the body usually tries to make around these infected areas and the poor blood perfusion that results. Purulent and necrotic debris may bind and inactivate some antibiotics. Heart failure and shock results in decreased distribution due to decreased blood flow to tissues. Renal and hepatic diseases can affect protein binding (hypoproteinemia). OLDS COLLEGE AHT 1170 A-31 Drug Metabolism Explain absorption and the methods of absorption. Also known as biotransformation. Describe factors that affect absorption. This is the body's ability to change a drug chemically from the form in which it was administered into a form Explain drug distribution. that can be eliminated from the body. Identify factors that affect the distribution rate of A drug that has undergone a chemical change is said drugs. to be metabolized (a drug that is altered is called a  Explain drug metabolism. metabolite). Describe routes for the elimination of drugs. Not all drugs are metabolized (i.e. some drugs circulate and are excreted in an unchanged form from that which Explain the concept of drug half-life. they were administered). Describe disease states The enzymatically mediated chemical changes which that could affect drug excretion. metabolize a drug can: 1. Reduce activity/toxicity of drug (most common). 2. Increase activity/toxicity (not common). 3. Change it to a form that is readily excreted. Some drugs require metabolism before achieving active form (e.g. primidone is converted to phenobarbital; it is the metabolites of antifreeze which are toxic); whereas, most drug metabolites are inactive. Metabolism/Biotransformation Mainly occurs in the liver, but also kidney, lung and nervous tissue, blood, gut wall, and gut content (bacteria). Liver has microsomal enzymes contained in hepatocytes. Amount of enzymes available depend on: - Species: (e.g. cats have limited ability to metabolize barbiturates, narcotics, acetaminophen, and aspirin). - Age: young have undeveloped liver enzyme systems; old have decreased ability to synthesize enzymes. - Sex: anabolic steroids of males increase metabolic enzyme production. - Stress: may have decreased metabolism in a stressed animal. - Nutritional status: if malnourished, not enough raw material to produce enzymes. - Disease: especially liver disease. OLDS COLLEGE AHT 1170 A-32 - Enzyme induction: the repeated administration of certain drugs will cause an increase in the enzymes that metabolize that drug (this may also be referred to as metabolic induction). Examples of drugs that cause enzyme or metabolic induction are barbiturates, and narcotics and in humans - alcohol. First Pass Effect This is an important concept to remember only when considering the effect of oral administration of drugs. When orally administered drugs are absorbed from the gut, they then enter the portal circulation. The blood in the portal veins is filtered by the liver before entering the systemic circulation. Therefore, these drugs are exposed to metabolic enzymes before they enter the systemic circulation, so some of the drug may be metabolized before it reaches the systemic circulation; thus, various target sites beyond the GIT. For some drugs, the amount of drug that is metabolized by the first pass effect is so large that it makes oral administration of these drugs ineffective. Example: Oral diazepam for epilepsy in dogs is significantly metabolized into metabolites with very little anticonvulsant activity. Bioavailability is as low as 3%. OLDS COLLEGE AHT 1170 A-33 Diagram of First Pass Effect Udder Saliva Sweat Lungs Kidney Systemic Circulation Urine Hepatic Vein Liver Enzymes Portal Vein Bile Duct Feces Oral Drug Small Intestine Unmetabolized drug Metabolized drug Figure A3-3 Systemic circulation. Source: Olds College, (2003). OLDS COLLEGE AHT 1170 A-34 Routes of Elimination Explain absorption and the methods of absorption. 1. Renal Describe factors that affect The major route for drug excretion. absorption. The drug must be water soluble. Metabolism of the Explain drug distribution. drugs usually makes them water-soluble. If the metabolite Identify factors that affect is lipophilic, it tends to get reabsorbed back into the the distribution rate of circulation system through the kidney tubules. drugs. The kidneys must be healthy with normal renal blood flow. Explain drug metabolism. The lower urinary tract must also be functioning normally.  Describe routes for the elimination of drugs. 2. Biliary Excretion Explain the concept of The liver excretes drugs into bile (the highly lipid-soluble drug half-life. drugs may be excreted this way). Describe disease states that could affect drug The bile is secreted into the GIT. excretion. The drug may be eliminated in the feces. The drug may also be reabsorbed and enter the enterohepatic cycle (see previous diagram). 3. Intestinal Excretion Some drugs are secreted across the GIT mucosa by active transport. Drugs can also be excreted in gut secretions, especially ruminant saliva. Ruminants produce large amounts of alkaline saliva, which traps acidic drugs or metabolites. These drugs are then eliminated via the feces. 4. Glandular Secretions Salivary, mammary, and sweat glands, also male genitalia. Most important of these is milk - some drugs can be secreted unchanged, - especially basic, fat-soluble drugs, - potentially can affect nursing offspring or humans who consume it. Quantities of drug found in milk or meat, are called residues. Potentially dangerous: - allergic reactions, - resistant bacteria, and - cancer. 5. Lungs Gas anesthetics eliminated in expired air. OLDS COLLEGE AHT 1170 A-35 Half-life Explain absorption and the methods of absorption. The rate of drug loss from the body is estimated using Describe factors that affect the drug’s half-life. absorption. Half-life = the time required for the amount of drug Explain drug distribution. in the blood to be reduced by one half (i.e. the time Identify factors that affect the distribution rate of required to excrete half of the administered dose from drugs. the blood). Explain drug metabolism. It can dictate how frequently the drug must be given Describe routes for the (dose interval). elimination of drugs.  Explain the concept of drug half-life. Describe disease states that could affect drug excretion. Figure A3-4 Decrease in plasma concentrations of a drug with a half-life of 2 hours. After 2 hours the concentration is 50% of the original concentration. In the next 2 hours the concentration drops again by half. This 50% decrease of drug concentration every 2 hours continues until the drug is completely eliminated. Source: Bill, (2006). It is estimated that it takes approximately ten T1/2s to eliminate 99.9% of a drug from the plasma. This does not mean that all the drug is gone from the body and the animal is safe to eat for human consumption: Example: Drug may stay trapped in udder and thus could appear in milk longer than predicted by the drug half-life. OLDS COLLEGE AHT 1170 A-36 Learning Exercise A3-1 Explain absorption and the 1. What are some examples of disease states that could affect methods of absorption. the absorption, distribution, metabolism, or excretion of Describe factors that affect drugs? absorption. Absorption Explain drug distribution. Identify factors that affect the distribution rate of drugs. Explain drug metabolism. Describe routes for the Distribution elimination of drugs. Explain the concept of drug half-life.  Describe disease states that could affect drug excretion. Metabolism Excretion OLDS COLLEGE AHT 1170 A-37 References Bill, R. L. (2006). Decrease in plasma concentrations [Graph]. Clinical Pharmacology and Therapeutics for the Veterinary Technician (3rd ed., p. 81). St. Louis, MO: Mosby Elsevier. Drug distribution [Figure]. (2007). Olds, AB. Olds College. Ionization effects [Figure]. (2007). Olds, AB. Olds College. Pharmacokinetics [Figure]. (2012). Olds, AB. Olds College. Research Glossary (n.d.). In Scientists Against Malaria. Retrieved November 10, 2015, from http://www. scientistsagainstmalaria.net/research/glossary. Systemic circulation [Figure]. (2003). Olds, AB. Olds College. OLDS COLLEGE AHT 1170 A-38 Module A4 Identify characteristics of adverse drug reactions. Source: Olds College, (2011). Drug Reactions As an RVT, you must be aware of any possible drug interactions, if more than one drug is being used at the same time in our veterinary patients. We also need to observe for possible adverse animal reactions to drugs. In describing adverse drug reactions, you will: describe multiple drug therapy, and describe adverse drug reactions. OLDS COLLEGE AHT 1170 A-39 Multiple Drug Therapy  Describe multiple drug therapy. If using more than one drug, you must be aware of possible Describe adverse drug interactions between those drugs. These interactions can be reactions. useful or harmful. Three Useful Interactions 1. Summation (Additive) Using two or more drugs that elicit the same type of response. Smaller amounts of each drug can be used (safer) and the final response is equal to the sum of the individual responses to the drugs. RESPONSE Drug A + B Drug B Drug A TIME Figure A4-1 The summation or additive effect of drug therapy. Source: Olds College, (2009). 2. Synergism When the final response to using two or more drugs together is greater than the sum of the individual responses to the drugs. Example Clavamox® is Amoxicillin + Clavulanate Synergistin® is Ampicillin + Sulbactam Benzathine OLDS COLLEGE AHT 1170 A-40 Drug A + B RESPONSE Drug B Drug A TIME Figure A4-2 The synergism effect of drug therapy. Source: Olds College, (2009). 3. Antagonism Some drugs exert their effect by binding with a target cell receptor and eliciting a specific cell response. Degree of binding is called affinity. Agonist - a drug with a high level of affinity for the receptor, which elicits a specific response. Partial agonist: a drug that has a moderate level of affinity and may elicit a response. Antagonist: block another drug from combining with a receptor and does not elicit a specific response. Example of useful antagonism: Oxymorphone and naloxone (naloxone reverses the narcotic oxymorphone). Harmful Drug/Drug Interactions Alteration of a drug’s effect as a result of prior, or concurrent, administration of another drug can be desirable (as mentioned above) or undesirable. Examples of undesirable interactions where a mixture of drugs may: OLDS COLLEGE AHT 1170 A-41 1. Be Chemically Incompatible Chemical reactions between drugs. Example Penicillins will inactivate aminoglycosides if mixed in the same syringe. 2. Alter pH Drugs that change the pH of the GIT or kidney may interfere with absorption or excretion of another drug at that site. Example Acidifying the urine causes increased excretion of basic drugs and reabsorption of acidic drugs back into the systemic circulation. 3. Induce Enzymes When the same enzymes are required to detoxify (metabolize) different drugs, they can initially be overwhelmed when a second drug is administered with the first. As a result, drug detoxification and excretion rates are temporarily decreased and blood levels are maintained higher and longer than anticipated. Conversely, if the liver produces more enzymes (induced enzymes) to metabolize a certain drug, other drugs that are metabolized by these same liver enzymes will also be broken down faster, so must be given at higher doses or more frequently. Example Phenobarbital administration causes induction of liver enzymes that also metabolize dexamethasone, griseofulvin, chloramphenicol. 4. Compete for Plasma-binding Sites If a second drug has a greater affinity for plasma-binding sites than the first drug, the first drug will be displaced and the increased free active form of this drug could potentially be toxic. OLDS COLLEGE AHT 1170 A-42 Example Sulfonamides may displace highly protein bound drugs, such as warfarin. Patients should be monitored for enhanced effects of the displaced warfarin. Other Undesirable Drug Reactions 1. Outdated Drugs Some drug breakdown products are nephrotoxic. Example Tetracyclines. 2. Infusion Mixtures In general, avoid drug mixtures in infusion lines due to many documented drug-drug incompatibilities. Example Ampicillin is susceptible to inactivation in solutions containing dextrose. 3. Adsorption Some drugs adhere to surfaces. Example Insulin and diazepam adhere to IV infusion lines. 4. Light Sensitive Drugs Some drugs become unstable after a short length of time when exposed to light. Example Any drugs that are purchased in dark glass containers. 5. Effects of Food In general, food has a greater effect on the absorption of solid drug forms than on liquids. Some drugs should be given with food, while others should be given on an empty stomach. Example Drugs poorly absorbed in presence of food: ampicillin and tetracyclines. OLDS COLLEGE AHT 1170 A-43 Adverse Drug/Animal Describe multiple drug therapy. Reactions  Describe adverse drug reactions. An undesirable response to a drug by the animal. Mild to fatal. Can be due to characteristics of the drug, the quality of drug, the drug carrier, the dose administered, or the route of administration. Examples Allergic - skin rash, pruritis; - anaphylactic shock. Photosensitization. Organ damage (especially kidney and liver). Blood abnormalities - depression of WBC; - intra-vascular hemolysis. CNS - depressants; - ataxia; - seizures. NOTE: Reproductive (decreased fertility, abortion). Idiosyncratic drug response - unexpected or unusual response. Teratogenicity - damage to embryo/fetus. Carcinogenicity, cancer causing. Immunosuppression. References Additive effect [Graph]. (2009). Olds, AB. Olds College. Blood pressure monitor [Photograph]. (2011). Olds, AB. Olds College. Synergism effect [Graph]. (2009). Olds, AB. Olds College. OLDS COLLEGE AHT 1170 A-44 Module A5 Describe drug legislation and dispensing procedures. Source: Olds College, (2011). Drug Legislation & Dispensing Procedures An RVT needs to know which drugs can be dispensed, to whom, and with what conditions. It is imperative that a RVT knows which category a drug fits into, and the special regulations needed for some of these categories. While the veterinarian is responsible for prescribing medication, the RVT should be able to read and fill prescriptions accurately. The RVT must also be able to correctly label and dispense products to the clients. In describing drug legislation and dispensing procedures, you will describe the Authorized Medicine Sales (AMS) Regulation, define terms related to the Food and Drug Act, identify federal and provincial legislation relating to drugs, describe drug schedules, describe regulations regarding controlled and narcotic drugs, identify withdrawal times, identify the information required on a prescription, explain the importance of labelling drugs, and describe appropriate drug dispensing methods including compounded medications. OLDS COLLEGE AHT 1170 A-45  Describe the Authorized Authorized Medicine Sales Medicine Sales Regulation. Regulation  Define terms related to the Today’s consumer insists on complete freedom from drug Food and Drug Act. residues in their food supply. The proper use of drugs is Identify federal and beneficial in alleviating animal suffering through the treatment provincial legislation relating to drugs. and prevention of disease, but improper use of drugs may cause Describe drug schedules. undue suffering in animals and can lead to drug residues in food products derived from treated animals. Describe regulations regarding controlled and narcotic drugs. Food safety is the primary objective of the Authorized Medicine Sales (AMS) Regulation. This regulation allows the sale of Identify withdrawal times. certain veterinary drugs at lay outlets and helps ensure the Identify the information required on a prescription. safe use of drugs in production animals. License holders have a responsibility to provide the livestock producer with Explain the importance of labelling drugs. basic information on the safe use of drugs. Outlets other Describe appropriate than veterinary clinics must have at least one “Qualification drug dispensing methods, Certificate” holder present at all times. It is not the role of including compounded medications. certificate holders to provide the livestock producer with specific disease information pertaining to diagnosis or prescribing of drugs. Food and Drug Act Terms NOTE: Drug Mitigation - relief, alleviation. Any substance or mixture of substances manufactured, sold, or represented for use for the diagnosis, treatment, mitigation, or prevention of disease, disorder, abnormal physical state, or the symptoms thereof in man or animal. (Food and Drug Act, n.d.) Practitioner A person authorized by the law of a province of Canada to treat patients with any drug listed or described in the Prescription Drug List. Specifically a physician, dentist, or veterinarian licensed to practice in the province of his or her employment. (Guidance on drug establishment licences and drug establishment licensing fees, 2013) OLDS COLLEGE AHT 1170 A-46 Prescription An order by a practitioner directing that a stated amount of any drug or mixture of drugs specified therein be dispensed for the patient named in that order. A legal order for a specific patient with a specific condition requiring a specific drug with instructions as to dosage and use. Veterinary drug sales in the province of Alberta are subject to both federal and provincial legislation. Federal legislation takes precedence over provincial legislation. Provincial legislation cannot be less restrictive than federal legislation. Dispense To provide a drug pursuant to a prescription; does not include the administration of the drug. Federal Legislation Describe the Authorized Medicine Sales Federal laws are designed to protect consumers from the illegal Regulation. sale and inappropriate use of all types of medications, including Define terms related to the Food and Drug Act. those we refer to as Production Animal Medicines.  Identify federal and provincial legislation Food and Drug Act relating to drugs. Describe drug schedules. a) Health Canada and The Canadian Food Describe regulations Inspection Agency (CFIA) regarding controlled and narcotic drugs. Prohibits the sale of foods or drugs containing any Identify withdrawal times. harmful substances, protecting public safety and health Identify the information required on a prescription. Regulates all food, drugs, cosmetics, and devices marketed in Canada Explain the importance of labelling drugs. Bureau of Veterinary Drugs (BVD) is the branch Describe appropriate of HPB that deals with all aspects pertaining to drug dispensing methods, including compounded veterinary drugs medications. Is made up of physicians, pharmacists, and veterinarians via the Canadian Veterinary Drug Advisory Committee Establishes prescribing schedules (drugs may be moved to new schedules) OLDS COLLEGE AHT 1170 A-47 Provides conditions and standards under which drugs are manufactured and offered for sale Regulates biologicals and vaccines (CFIA) Dictates specific labeling requirements Feeds Act Sets the conditions under which drugs can be put into

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