Intro to Pharmacology PDF

Introduction ============ Veterinary technicians are an essential part of the health care team. One of the primary technician responsibilities is to administer drugs on the order of the veterinarian. Mistakes in any aspect of drug administration, dosage, drug, route or frequency can have serious co...

Introduction ============ Veterinary technicians are an essential part of the health care team. One of the primary technician responsibilities is to administer drugs on the order of the veterinarian. Mistakes in any aspect of drug administration, dosage, drug, route or frequency can have serious consequences. Thorough knowledge of the drugs commonly used in veterinary medicine is mandatory. What the technician cannot do ============================= - Diagnose - Prognose - Prescribe drugs - Initiate treatment- though some states have exceptions for emergencies - Perform surgery Why is pharmacology important for veterinary technicians? ========================================================= - **Pharmacology** is the study of how drugs behave in the body. Technicians apply this knowledge in practice as **clinical pharmacology** - It is important not just to know names and route, but to know why a drug is given to help protect the patient - The veterinary technician's knowledge of physiology and how a drug affects the patient's physiology is vital to understanding how a drug might also have an adverse effect on the patient, **adverse drug reactions**. Rules for safe drug usage: ========================== 1. All drugs are poisons with the potential to save or take a life - Selection, dose and mode of administration may all determine a drugs safety and potential benefit 2. No drug is a silver bullet - Drugs alter normal physiology and the beneficial effects of that must be weighed with the potential for negative physiologic effects - The drug's effect on the animal's physiology may be altered by the animal's gender, species, breed, age, disease state in addition to genetic and environmental variation 3. All doses are guesses - Because of the physiologic variables mentioned above, all doses calculated for a patient are a scientific guess based on how a group of animals is supposed to respond when given a particular drug - Drug doses must be modified by the veterinarian based on the variables of the patient 4. Complacency kills - Since veterinary practices often use a small group of drugs for the majority of patients - Familiarity and successful outcomes can lead to complacency and the expectation that all patients will respond positively - Remembering rules 1,2, and 3 helps veterinarians and veterinary technicians remain vigilant for adverse effects Terms ===== - **Indications** the reasons for using a drug - **Contraindications** the reasons for NOT using a drug - **Pharmacokinetics** what happens to a drug once it enters the body - **Pharmacodynamics** how drugs exert their effects on the body Veterinarian-client-patient relationship (VCPR)- AVMA definition ================================================================ AVMA definition of VCPR Drug Sources ============ - Plant and mineral sources - Plants contain alkaloids, glycosides, gums, resins and oils - Examples: alkaloids end in --ine= atropine, glycosides end in --in= digoxin - Mineral sources for potassium, sodium, chloride - Bacteria and mold produce many antibiotics and anthelmintics - Hormones- formerly animal sources, currently synthetic sources - Recombinant DNA sources Inactive ingredients ==================== - Binders, coatings, preservatives, flavorings, etc. Pharmacotherapeutics -------------------- - Veterinarians determine diagnosis and determine the plan of treatment based on history, physical exam, laboratory test and diagnostic procedures - The drug is selected by one of three methods - **Diagnostic**- based on a definitive diagnosis - **Empirical**-based on clinical experience and common sense - **Symptomatic**-used to treat symptoms when a definitive diagnosis has not been determined - **Treatment regimen** - Route - Dosage - Frequency - Duration - **Prescription Drugs** - **When, according to the U.S. Food and Drug Administration (FDA) a drug has potential toxic effects or must be given in a way that requires trained personnel the drug is approved for use under the supervision of a veterinarian** - Labeled with the **legend statement**: - **Caution: Federal law restricts the use of this drug to use by or on the order of a licensed veterinarian** - Labels "For veterinary use only" or "sold only to veterinarians" [DO NOT] designate a prescription drug - Use of a prescription drug requires a valid VCPR - Veterinarians have the discretion to use a drug in a way not designated on the label if they take responsibility for the outcome= **extra label drug use (EDLU) or off label use** - However, if there is a labeled (veterinary or human) drug available for the intended indication, the labeled drug must be used - Example: Rimadyl® (carprofen) could be used as an injectable non-steroidal anti-inflammatory in cats when there was no product available for this indication, but when Metacam® (meloxicam) became labeled for this indication, it became the legal option for this indication - **Over-the counter (OTC) drugs** - Drugs that do not have enough potential for toxicity or do not require special administration - **Controlled substances** - Drugs that have the potential for human abuse or dependence - Determined by the **Drug Enforcement Administration (DEA)** The technician's responsibilities ================================= - **Right Drug**- be sure the correct drug is administered - **Right Dose**- the intended dose was given - **Right Route**- administer the drug by the correct route - **Right Time**- administer the drug at the correct time - **Right Patient**- administer the drug to the correct patient - **Right Documentation**- create and affix accurate labels, record the appropriate information in the medical record or controlled substance log - Careful observation of the animal's response to the drug - Question any orders that are not clear - Explain administration instructions and potential side effects to clients - Note and record **adverse drug reaction** ANY undesirable response to the drug. Can result from the drug itself, its quality or purity or the dose of the drug. Can include dermatitis, anaphylactic shock, photosensitivity, idiosyncratic drug reactions are unusual or unexpected Names, Regulations, Development, Agencies ----------------------------------------- Drug names ========== 1. Chemical- describes molecular structure, complex and impractical 2. Code or laboratory- used and given during research and development 3. Compendial- the name listed in the *United States Pharmacopoeia (USP)* legally accepted lists of drugs and standards for their quality and purity usually the same as the generic name 4. Official- usually the same as the compendial or generic 5. **Proprietary or trade name**- name chosen by the manufacturing company, federal copyright and trademark laws protect this name. Distinguished by a superscript R with a circle around it after the name: Tylenol®, Rimadyl®, and Banamine®. Names begin with a capital letter. 6. **Generic**- common name chosen by the company, not the exclusive right of the company and may be the same as the compendial name. Names begin with a lower-case letter. For example: Advil® versus ibuprofen Manufacture's Drug Labels ========================= The Center of Veterinary Medicine of the FDA requires that all drug containers show: - Drug name, generic and trade - Drug concentration and quantity - Name and address of the manufacturer - Controlled substance status - Manufacturer's control and lot number - Drug's expiration date - Storage instructions - Drugs intended for animals consumed by humans must have the appropriate withdrawal time written on the label - List of instructions for use and warnings about possible adverse effects - This added information is usually included on an insert in the container or as a tear off on the label - Trade name is usually listed first, followed by the generic name - Some drugs are available in different concentrations- concentration should be listed in bold - **Controlled substance status** is listed on those drugs with the potential for human abuse - These drugs are divided into schedules or categories - Designated with a capital C followed by a Roman numeral Development of new drugs ======================== - The federal government requires that any new animal health product to have its safety and efficacy rigorously tested - The estimated cost for 7-10 years of testing is about 50-100 million dollars Four regulatory agencies are involved: - **FDA**- Food and Drug Administration Regulates development and approval of animal drugs and feed additives - **EPA** -Environmental Protection Agency Regulates the development and approval of animal topical pesticides - **USDA**- U.S. Department of Agriculture Regulates the development and approval of biologics (vaccines, serums, antitoxins) - **DEA**- Drug Enforcement Administration Regulates drugs with the potential for human abuse, controlled substances. Steps in Development ==================== - Preliminary trials on simple organisms - Preclinical (animal safety) trials - Clinical trials for safety and efficacy - New animal drug application is submitted to the FDA - Final review by the FDA - Product monitoring - *The Green Book-* a list of all drugs that have been approved by the FDA for safety and efficacy. Available electronically at: - The Animal Medicinal Drug Use Clarification ACT (AMDUCA) ======================================================== Passed in 1994, it essentially made the practice of veterinary medicine legal! This legislation made the extra label use of approved veterinary drugs legal under specific well-defined conditions. - Previously veterinarians could use any drug that could be obtained legally and left no food residues - The FDA then tightened its rules to make any extra label use illegal- this meant any use that was not specifically on the label was not legal. Often drugs are labeled for only one species but must be used in many to provide care- this made it impossible to practice veterinary medicine and adhere to the law. - AMDUCA allows veterinarians to legally select the most efficacious drugs for their patients.  Label requirements for EDLU  Compounding of Veterinary Drugs =============================== - Because of the variety of species veterinarians on called on to treat, there may not always be an approved drug for every clinical situation - Any alteration of a drug by a veterinarian or her/her employee constitutes a new animal drug, which is subject to FDA approval - Recognizing this, the FDA issued a directive to define the conditions for which compounding is permitted: 1. Legitimate veterinary medical need 2. Need for an appropriate regimen for a particular species, size, gender, or medical condition 3. Lack of an approved animal or human drug which when used as labeled will treat the condition 4. Too long a time interval for securing the drug to treat the condition The AVMA policy on compounding follows: Text from the AVMA policy on compounding - The rules of veterinary compounding have been in the veterinary headlines recently because of the tendency to use compounded formulation, not for the reasons enumerated above, but for economic reasons - Cost savings is NOT an accepted justification for compounding - Compounded drugs, from bulk drug are illegal, but significantly less expensive than the approved products - Example: compounded trilostane, versus FDA approved Vetoryl® or compounded pergolide, versus FDA approved Prascend® Veterinary Feed Directive (VFD) =============================== - Established as "an alternative to prescription status" for certain antimicrobial animal feed additives - Use of VFD requires a valid VPCR and the issuance of a VFD form from the veterinarian which must be presented at the feed mill to purchase medicated feed - Often used in raising poultry or in feedlots Minor Use and Minor Species Animal Health Act (MUMS) ==================================================== - There is a shortage of approved animal drugs intended for use in less common species or for less common conditions - Sheep, goats, game birds, llama, deer, elk etc. - Is also designed to provide major species (dogs cats, horses, cattle, etc.) with needed drugs for uncommon indications Dispense versus prescribe ========================= - Veterinarians prescribe and dispense drugs (physicians typically just prescribe) - Sometimes a profit center, though this is becoming less common because of competition from online pharmacies - More frequently done because human pharmacies rarely stock approved veterinary drugs Marketing of drugs ================== - Veterinarians obtain pharmaceuticals either directly from the manufacturer or through a licensed distributor - Distributors purchase their supply directly from the manufacturer - "Sold only to graduate veterinarians" does not indicate the drug is prescription, only the company's policy - Feed companies sometimes sell similar OTC products at a price lower than veterinarians can offer because of bulk purchasing - Feed companies cannot legally sell prescription drugs - check your local feed store, do they sell drugs marked: - **Caution: Federal law restricts the use of this drug to use by or on the order of a licensed veterinarian?** Internet pharmacies =================== - Concern that internet pharmacies may be selling drugs without a valid VCPR - **Drug diversion-** the sale of drugs from illegitimate sources - Most manufacturers will not sell directly to internet pharmacies so drugs may pass through many hands prior to sale online - Potential sale of counterfeit drugs - **VIPPS**= Verified Internet Pharmacy Practice Sites^®^ to validate the online pharmacy is appropriately licensed and is conducting business legitimately Drug Enforcement Administration (DEA) ===================================== Regulates drugs with the potential for human abuse. Drugs determined to be a risk are called **controlled substances** or **scheduled drugs.** These drugs are designated with a capital C and a Roman numeral. Veterinarians may not prescribe controlled substances without registering with the DEA. Drugs are scheduled depending on the risk of abuse CI-V. [C- I drugs:] Extreme risk of abuse and no approved medical use. Heroin, LSD and marijuana are included in this category. [C- II drugs:] May be prescribed by veterinarians but have the most potential for abuse. Morphine, fentanyl, medical cocaine and methylphenidate hydrochloride, Ritalin™ are included in this category. Ordering these drugs requires submission of DEA from 222. Drugs in this category must be logged separately from all other controlled substances. The logs must be immediately available for review by DEA agents during inspection. [C- III drugs:] These drugs have low to moderate potential for abuse. Ketamine, phenobarbital, anabolic steroids and many euthanasia solutions. [C- IV drugs:] Drugs have low potential for abuse, but use may lead to physiological or psychological dependency. Butorphanol, tramadol and benzodiazepines are included in this group. [C- V drugs:] Drugs with low potential for abuse and subject to state and local regulations. In many states, gabapentin is in in this category. Most states now require DEA registrants to register with their Prescription Drug Monitoring Program (PDMP) and report the drugs they dispense to the monitoring program to search for patterns of abuse. In Colorado, controlled substances must be dispensed through a human pharmacy to comply with PDMP regulations. - Controlled substances must be stored in a substantially constructed, locked cabinet with controlled access. Registrants must ensure no one with a controlled substance felony conviction or who has surrendered DEA registration from having any access to controlled substances. - Disposal of unused or expired controlled substances requires the drugs to be rendered "unrecoverable" or returned to a reverse distributor. Both methods require documentation.