General Pharmacology Introduction Lecture Notes PDF

Dr. Mostafa Kamal Mohammad Lecturer of Pharmacology and Toxicology Faculty of Pharmacy Introduction  Lecture topics 1. What is pharmacology Definition Branches 2. What is drug Definition Sources Nomenclature Routes of administration  Pharmacol...

Dr. Mostafa Kamal Mohammad Lecturer of Pharmacology and Toxicology Faculty of Pharmacy Introduction  Lecture topics 1. What is pharmacology Definition Branches 2. What is drug Definition Sources Nomenclature Routes of administration  Pharmacology pharmakon Ology mean mean Drug or Medicine Science Branch of knowledge Pharmacology can be defined as the science which deals with drugs. Pharmacokinetics Pharmacodynamics Toxicology Posology Pharmacology Screening Bioassay Pharmacotherapeutics Clinical pharmacology  Pharmacokinetics: is the branch of Pharmacology which concerns “Effect of the body on the drug" Pharmacodynamics: is the branch of Pharmacology which concerns “Effect of the drug on the body"  Pharmacotherapeutics: is the branch of Pharmacology which study the therapeutic uses and effects of drugs. Clinical pharmacology: is the branch of Pharmacology which represents the scientific study of drugs in humans to optimize drug therapy in clinical cases.  Toxicology: is the branch of Pharmacology that deals with toxic changes and adverse effects in living organisms induced by drugs. Drugs are chemical or biological substances used to change the state of body functioning for:  Diagnostic: -Radioactive dyes. - Dilating drops during eye exams.  Preventive: Vaccines, Aspirin (Antiplatelet)  Treatment or relieve symptoms: Paracetamol  Curative: Antibiotic  Health maintaining: Vitamins  Drug sources There are four sources of drugs 1) NATURAL SOURCES: Plants Animals or human Insulin  pork and beef pancreas Atropine  belladonna Steroids testosterone – hydrocortisone Caffeine coffee Polysaccharides  heparin Minerals Microorganisms Ferrous sulfate  iron deficiency anemia. Antibiotics Magnesium sulfate  purgative. Penicillin or Aluminum hydroxide  peptic ulcer. tetracycline Drug sources 2) Semisynthetic Sources  Chemically modifying substances  available from natural source  to improve its potency, efficacy and also reduce side effects.  Ethinyl estradiol from Estrogen hormone.  Amoxicillin from Penicillin. Heroin from Morphine. 3) Synthetic Sources  This includes completely new structures  obtained by chemical synthesis and subjected to screening tests. Ex: Aspirin, paracetamol, oral antidiabetics, antihistamines, general and local anesthetics. Q) Advantages of synthetic drugs are:  Chemically pure.  Easier and cheaper process.  Excellent quality ??.  Since the pharmacological activity of a drug depends on its chemical structure and physical properties, more effective and safe drugs can be prepared by modifying the chemical structure of the prototype drug. 4) Biosynthetic Sources This type concern with synthesis of new drugs through series of physiological process in living organisms using molecular biology and recombinant DNA technology. Biosynthetic insulin / Hepatitis B vaccine  Drug nomenclature  Drugs may be named according to one of the following systems:  Chemical name  according to organic chemistry rules.  Generic name  the official name of the drug used in pharmacopoeias and pharmacology books.  Trade name  is denoted by the manufacturer or pharmaceutical company.  NHCOCH3 OCOCH3 COOH OH 1 2 Chemical name: Chemical name: Acetylsalicylic acid N-acetyl-para-aminophenol. Generic name: Generic name: Aspirin. Acetaminophen, paracetamol. Trade name: Trade name: Rivo®, Aspirin®. Panadol®, Abimol®  Routes of drug administration 1. Enteral Routes 3. Topical Routes 2. Parenteral Routes  Injection  Oral  Buccal  Sublingual  Respiratory tract  Rectal administration  1. Enteral Routes  Drugs administrated through the alimentary canal from (mouth to anus): a- Oral rout (P.O.): It is the most convenient, widely used, economic and safe rout of administration. Disadvantages:  Irritant drugs can cause nausea and vomiting.  Some drugs can de destroyed by gastric acid or alimentary enzymes eg. Insulin.  Some drugs form complexes with food.  Drugs are affected by hepatic first pass effect.  Not suitable in cases of emergency.  Cannot be used in unconscious patients. b- Buccal or sublingual:  Buccal: A tablet or lozenge is placed in the mouth in contact with the buccal mucosa and this allows for absorption of small, lipid-soluble molecules through the epithelial lining of the mouth.  Sublingual: Tablet can be placed under the tongue (sublingual) and the drug is absorbed from the sublingual veins. Advantage: Faster rout to the heart itself via the blood circulation. Drug is protected from first-pass metabolism of the liver. C- Rectal route:  Drugs are administered in the form of liquids (enemas) or suppositories.  Absorption takes place through the mucosal surface and rectal veins.  The lower two-thirds of the rectum allow for direct systemic absorption bypassing hepatic first-pass effect advantages: Unconscious patient. Nauseous or vomiting clients. Swallowing problems. Avoid the destruction of the drug by the gastric acid.  2. Parenteral Routes Means delivery of drugs by any rout other than alimentary or topical routs a- Injection 1. Intra-dermal injection: The drug is injected in the dermis to minimize systemic absorption and toxicity. e.g. allergic skin tests. 2. Subcutaneous injection (S.C): - The drug is injected under the skin - The rate of drug absorption is slower due to less vasculature. - Some drugs in which slow absorption is necessary are given S.C, e.g. insulin and adrenaline 3. Intra-muscular injection (I.M): - The drug is injected in the form of solution or suspension deep in skeletal muscles. - Drug absorption rate is dependent on lipid solubility of the drug, vehicle composition and vascularity of the injected region. 4. Intra-venous injection (I.V): - The drug is injected directly into venous blood. Advantages: - Rapid action. - Most suitable in emergency cases. - 100% bioavailability. - Large volumes of drugs. - Irritant drugs. 5. Intra-arterial injection (I.A): - The drug is injected into an artery to attain high drug concentration in a tissue or an organ before being diluted in the general circulation. 6. Intra-articular injection : - This route for direct injection of a drug inside a joint is required. e.g. corticosteroids in arthritis. 7. Intra-thecal injection : The drug is injected into the spinal fluid b- Respiratory tract administration 1. Intra-nasal administration: - The drug is administered to the nasal mucosa in the form of drops or spray for the purpose of local (e.g. decongestants) or systemic effects. 2. Pulmonary inhalation: - The drug is administered by various devices like metered dose inhalers (MDI), spacers, nebulizers or dry powder aerosols. - Drug absorption from the bronchial tree is very rapid and avoids hepatic first-pass effect.  3. Topical and Transdermal Routes Topical route: drugs may be applied on the skin for local effects (to avoid systemic toxicity or to localize drug effect) and examples are antimicrobials and local anesthetics. Transdermal route: is the placement of a drug formulation (lotion, ointment, cream, paste or patch) on the skin surface for systemic absorption. Other topical routes of administration include: - Eye, ear and nose drops. - Urethral or vaginal solutions. - Mouthwashes and gargles. Note: There is a difference between Route and effect Route: (Enteral – Parenteral – Topical) Effect: (Local – Systemic)  Conclusion  Pharmacology definition and branches  Drugs definition, Sources, Uses  Drugs Nomenclature  Drugs routes of administration