Introduction to Pharmacology Lecture - Dosage Forms and Administration - PDF

This Document has been modified with Flexcil app (Android) https://www.fexcil.com Basic pharmacology Introduction to pharmacology Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document has been modified with Flexcil app (Android) https://www.fe...

This Document has been modified with Flexcil app (Android) https://www.fexcil.com Basic pharmacology Introduction to pharmacology Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document has been modified with Flexcil app (Android) https://www.fexcil.com Introduction to pharmacology Lecture ILOS 1- Define some pharmacological terms. 2- List different natures and sources of drugs. 3- Recognize different forms of the drugs. 4- Recognize different routes of drug administration with their advantage and disadvantages. Lecture items 1- Key terms and sources of drugs. 2- Dosage forms of drugs. 3- Routs of drug administration. 2 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note This Document has been modified with Flexcil app (Android) https://www.fexcil.com 3 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document has been modified with Flexcil app (Android) https://www.fexcil.com Introduction to pharmacology 1- What is the Pharmacology? - Is the science that deals with the mechanism of actions, uses and adverse effects of drugs. - Does not include pharmacy, which is the preparation and dispensing of drugs. 2- What are the Drugs? Are chemical agents that stimulate or inhibit an existing cell functions, but not create new one. 3- What are the Pharmacogenetics (idiosyncrasy) and Pharmacogenomics? a. Pharmacogenetics: focuses on how a single genetic variation may affect drug metabolism, efficacy, and toxicity. b. Pharmacogenomics: on the other hand, considers all a person's genes and how they may influence their drug response. 4- What is the Pharmacodynamics? Is what drugs do to the body. It is the study of the biological and therapeutic effects of drugs and the mechanism of their action. 5- What is the Pharmacokinetics? Is what the body does to the drugs. It is study of the kinetics of drug absorption, distribution, metabolism and excretion. 4 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note This Document has been modified with Flexcil app (Android) https://www.fexcil.com 5 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction This Document has to pharmacology been modified with Flexcil app (Android) https://www.fexcil.com Nature and Sources of Drugs 1. Plant sources: § Bark of Cinchona → Quinine. § Leaves of belladonna → Atropine. § Juice of opium poppy → Morphine. 2. Animal sources: Insulin from pork and beef, vaccines, sera and vitamins. 3. Synthetic sources: As aspirin, sulphonamides and local anaesthetics. 4. Mineral sources: Iron used in hypochromic anaemia, iodine used in hyperthyroidism, magnesium sulphate used in treatment of constipation. 5. Microorganisms: antibiotics e.g. penicillins. 6. A new technology, called genetic engineering - Has allowed production of drugs that are identical to human hormones. - This technology is used to manufacture insulin, hepatitis B vaccine and several other products 6 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Dosage forms of drugs What are available dosage forms of drugs? 1- Liquid forms. 2- Solid forms. 3- Preparation for external use. 7 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Dosage forms of drugs 1- Liquid drugs Liquid drugs usually consist of a powder dissolved in a liquid - Solutions are preparations that contain the drug dissolved in a solvent, usually water 1- Solutions (For example, 5%dextrose in water). - Suspensions are drugs that do not remain dissolved. After sitting for even short periods, these drugs will tend to separate. - They must always be shaken well before use (e.g., penicillin preparations). 2- Suspensions Often drugs suspended in sugar and water to improve the taste. (e.g., cough syrup). 3- Syrups - Liquid drugs which are administered into the body through IM, IV or SC routes are called parenteral drugs. 4- Parenteral drugs - Most drugs used in emergency medicine are parenteral. 8 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Dosage forms of drugs 2- Solid drugs 1- Pills Easy to swallow. - Tablets are similar to pills. 2- Tablets - They are composed of a powder that has been compressed into an easily swallowed form and are often covered with a sugar coat to improve taste. § Suppositories are mixed into a base that is solid at room temperature (approximately 21 C). § When placed into the body either rectally or vaginally, they dissolve and are then absorbed 3- Suppositories into the tissue. - Are small containers of drugs made of gelatin’ A- Hard gelatin capsules: Usually contain powdered drugs. 4- Capsules B- Soft (flexible) gelatin capsules: Contain a liquid solution or Suspension - These are long-acting oral preparations. 5- Sustained- - They are formed of groups of drug particles each is coated with special envelope that dissolve at different dissolution rates to give a long-acting effect, e.g., antihistaminics. released tablets and capsules 9 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note. Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Dosage forms of drugs 3- Preparations intended for external use (Topical applications) - They are applied on the surface of skin or mucous membranes: a. Ointments, lotions and solutions are applied to the skin or mucous membranes. Eye, nasal drops, is also used topically. b. Enema can be applied into the rectum. 10 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration 11 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration What is the classification of routes of drug administration? 12 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration What factor does the choosing of the rout administration depend on? - The choosing of the rout depends on the desired effect: whether (a local or systemic). What are the characteristics of localized drug? 1- Concentrating drug at the desired site of action 2- Minimizing systemic side effects. When to use the systemic approach? Is used when the target tissue is inaccessible by direct administration or application. 13 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration A- Local administration In local administration the drug is applied directly to the desired locality in an adequate concentration in a suitable vehicle. This is achieved by: Ophthalmic a-Topical application. b- Inhalation. c-Injection 1- Topical application: OTIC TOPICAL Intranasa 2- Inhalation: - Introducing drugs directly into the respiratory tract for the treatment of broncho-pulmonary diseases. INTRAUTERINE e.g., Beta agonists, corticosteroids, anti- cholinergic and mast cell inhibitors for treatment of bronchial asthma 3- Injections: The drugs are injected around sensory nerve terminals (infiltrative anaesthesia)or around nerve trunk nerve block or even in the joints (intra articular injection of corticosteroids. 14 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  Introduction to pharmacology This Document has been modified with Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration B- Systemic administration In order to obtain a systemic or general effect from a drug, it must be adequately absorbed from its site of administration and carried by the circulation to the different body tissues. 1- Alimentary routes (Enteral): Mouth (swallowed) or oral. Buccal (sublingual). Rectum. 2- Parenteral routes: Intravenous injection or infusion. Intramuscular injection. Subcutaneous injection or infusion. Inhalation. IM (Intramuscular) SC (Subcutaneous) IV (Intravenous) 15 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note This Document has Introduction been modified withto pharmacology Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration B- Systemic administration B.1- Alimentary (Enteral) Routes 16 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.1- Alimentary (Enteral) Routes B.1.1- Oral route What is the characteristics of oral route? The drug should be palatable, non-irritant, stable at the pH of the stomach (acid resistant), unaffected by digestive juice. What are advantages of oral route? Safe, self use, easy, no need for sterilization and economic What are disadvantages of oral route? 1. Delayed onset of action, so unsuitable in emergency situations. 2. It is NOT practical in unconscious or uncooperative patients. 3. Some drugs are destroyed in the GIT (insulin, oxytocin , some penicillin). 4. Some drugs are not absorbed from the gut (streptomycin) and should be given parenterally if a systemic effect is desired. 5. Some drugs are absorbed from GIT but are inactivated in the liver before reaching the general circulation (glyceryl- trinitrate). 6. Some tablets when taken with too small quantity of water and in the supine position may lodge in the esophagus with delayed onset and even ulceration. 17 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.1- Alimentary (Enteral) Routes B.1.2- Buccal for systemic effect (Sublingual) Advantages:. Quick effect as the oral mucosa has an abundant blood supply.. The possibilities of degradation by gastric acid, delayed effect by slow gastric emptying, or first-pass metabolism in the liver is avoided.. The effect can be terminated by spitting out the tablet. Disadvantages:. Irritation of the mucous membrane.. Excessive salivation promotes swallowing so losing the advantage of this route e.g , glyceryl trinitrate and nifedipine. 18 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.1- Alimentary (Enteral) Routes B.1.3- Rectal administration Advantages:. A drug irritant to the stomach can be given by rectum.. Avoids gastric acid and enzymes.. Absorption relatively rapid.. May partially avoid hepatic first-pass metabolism.. Can be used in patients unable to swallow or who are vomiting.. Sometimes prolongs drug action due to prolonged absorption. Disadvantages:. Psychological, many patients refuse this route.. Rectal inflammation may occur with repeated use.. Absorption can be unreliable, especially if the rectum is full of faeces e.g, Aminophylline, indomethacin, ergotamine, phenobarbitone 19 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document has Introduction been modified withto pharmacology Flexcil app (Android) https://www.fexcil.com Routes of Drug Administration B- Systemic administration B.2- Parenteral Routes Parenteral Administration: This term is used to describe any route of administration of a drug, which does not make use of the gastrointestinal tract, respiratory tract, or the skin. - The most common parenteral routes are intravenous, intramuscular, and subcutaneous injections. 20 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes General advantages of parenteral routes:. Suitable to uncooperative, unconscious, or nauseous patients.. Drugs that are normally (not effective, poorly absorbed, or inactive) orally can be effectively administered.. Intravenous route provides immediate onset of drug action when needed during emergency situations.. Other parenteral routes can be used to slow onset and/or prolong duration of drug action.. Patient compliance problems are largely avoided.. Can be used to correct patient fluid and electrolyte imbalance and provide nutrient and caloric requirements. General disadvantages of parenteral routes:. Administered by trained personnel.. Require aseptic procedures.. Pain is inevitable.. Drug effects are difficult to reverse.. May be inconvenient when frequent dosing is required. 21 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes B.2.1- Intravenous administration B.2.1.a Direct Advantage: Suitable for: - Rapid action (emergency) - Patient (Vomiting &unconscious). - High bioavailability. - Drugs (Irritant & Bad taste). - No food-drug interaction Not suitable for: - No first pass metabolism - Oily solutions. - No gastric irritation. - Poorly soluble substance. Disadvantage Dosage form: - Only suitable for water soluble drugs. Vial or ampoule. - Some infection - Need Sterilization. - Pain. - Needs skill. - Anaphylaxis. - Expensive. 22 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes B.2.1- Intravenous administration B.2.1.b infusion Why do we use intravenous infusion? To provide patient with fluid when adequate fluid intake cannot be achieved through oral route. When the patient is unable to swallow, e.g. unconscious patient. When it is undesirable for the patient to take fluids or food by mouth e.g. post operative patients. To keep the vein open for administration of drugs or when waiting for blood transfusion. To maintain and correct electrolytes of the body when the patient is losing fluids or salts in excess like in persistent diarrhoea and vomiting or in severe burns. 23 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes B.2.2Intramuscular injection Advantages:. Rapid absorption.. Used for lipid-soluble or water-soluble drugs.. Can be used to prolong drug action if drug given in viscous oily vehicle e.g., fluphenazine decanoate.. Avoids first pass metabolism.. Absorption improved by exercise of muscle (increase blood flow). Disadvantages:. Requires well trained personnel.. Painful and no self administration.. Needs sterilization.. Can give poor absorption if drug precipitates at injection site e.g, Phenytoin, diazepam.. Absorption decreased by e.g. haemorrhage, shock, heart failure.. Injury to nerve , irritation and abscess formation. 24 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes B.2.3- Subcutaneous route Advantage of subcutaneous: Onset of drug action faster than oral. Avoids gastrointestinal absorption problems. Disadvantage of subcutaneous: Must involve sterile technique because breaks skin barrier. More expensive than oral. Can administer only small volume. Slower than intramuscular administration. Some drugs can irritate tissues and cause pain. 25 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note  This Document hasRoutes of Drug been modified Administration with Flexcil app (Android) https://www.fexcil.com B- Systemic administration B.2- Parenteral Routes B.2.4- Inhalation as systemic route Examples: 1- General anaesthesia 2- Nitrous oxide administration. 3- Inhaled analgesics Advantages:. Rapid absorption for systemic action.. High concentration attainable for local effect.. Self administration possible.. Very close to IV absorption for volatile anesthetics. Disadvantages:. Irritation of pulmonary epithelium.. Poor regulation of dosage. 26 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note This Document has been modified with Flexcil app (Android) https://www.fexcil.com THANK YOU 27 Flexcil - The Smart Study Toolkit & PDF, Annotate, Note