Orientation & Introduction to Pharmacology - B52, 2024 PDF

Orientation & Introduction to Pharmacology – B52 Date: 15.04.2024 Dr Basanta Kumar Mohanty, Professor & HOD, Department of Pharmacology A. Department Goal Department of Pharmacology at MUCM aims to provide students a solid grounding on the basic concepts of pharmacology which forms the basis for mak...

Orientation & Introduction to Pharmacology – B52 Date: 15.04.2024 Dr Basanta Kumar Mohanty, Professor & HOD, Department of Pharmacology A. Department Goal Department of Pharmacology at MUCM aims to provide students a solid grounding on the basic concepts of pharmacology which forms the basis for making clinical decisions in pharmacological management of commonly occurring health problems during clinical practice. Manipal University College Malaysia 2 B. Objectives After the completion of second year of MBBS program, the students at MUCM should be able to: 1. Apply pharmacology knowledge of commonly prescribed drugs to explain rationale for their use in primary care conditions, their adverse effects, contraindications and drug interactions. 2. Apply integrated knowledge across basic science disciplines to explain rationale for drug use in disease conditions. 3. Apply principles of rational prescribing to derive appropriate treatment for a disease condition. 4. Demonstrate self-directed learning skills in assimilating new medical information 5. Demonstrate the ability to report adverse drug reactions to monitoring center 6. Demonstrate skills of communicating drug related information to patient 7. Demonstrate the ability to retrieve the drug details from various sources of drug information and evaluate drug promotional literature 3 C. Recommended Textbooks 1. Principles of Pharmacology: H L Sharma and K. K Sharma, Paras Medical Publishers, 3rd edition, 2017 2. Basic and Clinical Pharmacology. Bertram Katzung, Susan Masters, Anthony Trevor. 13th edition (LANGE Basic Science), 2014 D. Reference books 1. Lippincott Illustrated Reviews: Pharmacology 6th edition (Lippincott Illustrated Reviews Series) 6th Edition [South Asian edition) 2015 2. Essentials of Medical Pharmacology: K. D. Tripathi, Jaypee Brothers Medical Publishers (P) Ltd, 8th Edition, 2018 E. Learning Outcomes Note: *** Must know, ** Desirable to know, * Nice to know 4 F. Self Directed Learning (SDL) There will be around three to four SDLs in each block. The topics with learning objectives will be notified to the students at the commencement of each block/before the SDLs. Students will be assessed on the specified topics in the form of MCQs test on the scheduled date or later during block examination or professional examination. 5 G. Practical Exercises Practical exercises will be in the form of prescriptions for a given clinical condition, case-based learning, questions related to the concepts of general pharmacology and rational prescribing (prescriptions), criticize, correct and rewrite the prescription (CCR), calculations, interpretation of graphs, demonstration of effect of drugs using computer software (CAL), Adverse drug reaction (ADR) reporting, dose calculations, fixed dose combinations (FDCs), emergency management, finding information of drugs using sources of drug information and doctor-patient communication (DPC) and problem solving exercise (PSE) etc. 6 H. Journals Students are expected to neatly record their assignments of practical exercises which are discussed in the practical classes. At the end of each block, the journals will be assessed for a maximum of 10 marks. The criteria for evaluation of the journal will be completeness, correctness, cleanliness and creativity. The marks obtained will be added to the practical component of each block examination. Manipal University College Malaysia 7 Introduction to Pharmacology Manipal University College Malaysia 8 Learning Outcomes 1. Define following terms: Pharmacology, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, clinical pharmacology, pharmacy, toxicology, chemotherapy, Pharmacoeconomics and pharmacoepidemiology.*** 2. Explain the following with examples: drug and prototype drug. *** 3. List different sources of drugs with examples. *** 4. Explain Essential Drug Concept. *** 5. Define the term orphan drugs with examples. ** Manipal University College Malaysia 9 History of Pharmacology ❖ Illness has been man’s heritage from the beginning of his existence and the search for remedies to combat it is equally primitive. ❖ Oldest known therapeutic writings from India and China ❖ India (3000 BC) – Rigveda and narrated in Charaka and Sushruta Samhita – Herbal and mineral preparations ❖China ( 2735 BC) - Pan Tsao - Plant and animal products and metallic preparations ❖Egypt’s papyri (1900 BC) – 700 herbal remedies ❖Babylonian clay tablet (700 BC) – 300 drugs ❖Modern medicine (450 BC) - Hippocrates, a Greek physician ❖Hippocrates: Concept of disease as a pathologic process and tried to organize the science of medicine based on observation, analysis and deduction. 10 History of Pharmacology ❖ Till the beginning of 19th century, the treatment of diseases included obnoxious remedies i.e., flesh, excreta, and blood of various animals, metals and plant preparations ❖Allopathy: James Gregory (1753-1821) propounded heroic treatment consisting of blood letting, forceful emesis and purging often with fatal results. This was labelled Allopathy (another suffering) still wrongly applied to the system of Modern medicine ❖ Homeopathy: Opposed to the principles of Allopathy, Hahnemann produced the principle of Homoeopathy (similar suffering); Like cures like and dilution potentiates the action of drugs. 11 History of Pharmacology Oswald Schmiedeberg (1838–1921) is generally recognized as the founder of modern pharmacology. Schmiedeberg obtained his medical doctorate in 1866 with a thesis on the measurement of chloroform in blood. He worked at Dorpat under Buchheim, succeeding him in 1869. In 1872, he became professor of pharmacology at the University of Strasburg, receiving generous government support in the form of a magnificent institute of pharmacology. He studied the pharmacology of chloroform and chloralhydrate. In 1869, Schmiedeberg showed that muscarine evoked the same effect on the heart as electrical stimulation of the vagus nerve. In 1878, he published a classic text, Outline of Pharmacology, and in 1885, he introduced urethane as a hypnotic. In his 46 years at Strasburg, Schmiedeberg trained most of the men who became professors at other German universities and in several foreign countries. 12 History of Pharmacology John Jacob Abel: Father of American Pharmacology. His major accomplishments include the isolation of epinephrine from adrenal gland extracts (1897– 1898), isolation of histamine from pituitary extract (1919), and preparation of pure crystalline insulin (1926). His student Reid Hunt discovered acetylcholine in 13 adrenal extracts in 1906. What is Pharmacology ❖ Derived from two Greek words Pharmakon (drug or active principle) and Logos (a discourse or treatise or science). It is the science that deals with drugs. ❖ Pharmacology consists of detail study of drugs particularly their actions on living animals, organs or tissues; the actions may be beneficial or harmful. ❖ It is defined as a science which deals with mechanism of action, therapeutic uses, adverse effects and fate of drugs in human beings or animals. ❖The objective of Pharmacology is mainly to provide the scientific data, using which one can choose a drug treatment of proven efficacy and safety from the various options available to suit the patient. ❖ There are various subdivisions of Pharmacology. 14 Sub-divisions of Pharmacology ❖ Pharmacokinetics (PK): Study of absorption, distribution, metabolism and excretion of drugs (ADME) and their relationship to pharmacologic response. ( What the body does to the drugs) Dose regimen Absorption Distribution Metabolism Elimination Pharmacokinetics Concentration in Plasma Concentration at site of Action ❖Pharmacodynamics (PD): Quantitative study of drug action including the site of action, mechanism of action, therapeutic and toxic actions. (What the drug does to the body) Pharmacodynamics Action Mechanism of action Adverse effects Effects observed Sub-divisions of Pharmacology ❖Therapeutics: It is concerned with prevention and treatment of diseases or relief of symptoms. The word means to care for. It not only involves the scientific knowledge and judgement but also skills, wisdom and sense of responsibility. ❖Toxicology: It is the science of poisons. It includes detection and knowledge of about the nature and effects of poisons as well as treatment of poisoning. Poisons are substances that cause harmful, dangerous or fatal symptoms in animals and humans and many drugs in higher doses act as poisons. ❖Chemotherapy: It deals with the effect of drugs upon microorganisms and parasites living and multiplying in humans and animals. It also includes treatment of cancer. 16 Sub-divisions of Pharmacology ❖Clinical Pharmacology: It is the systematic study of a drug in man, both in healthy volunteers and in patients. It includes the evaluation of pharmacokinetic and pharmacodynamic data, safety, efficacy and adverse effects of a drug. ❖Pharmacy: It is the science of identification, selection, preservation, standardisation, compounding and dispensing of medicinal substances. Clinical Pharmacy: It is the science of drug formulations, their stability, shelf life, handling and also education of the patient about compliance and counselling him on how to take the medication. It also includes monitoring for errors in drug therapy. The clinical pharmacist optimises the patient care with the help of the physician. 17 Sub-divisions of Pharmacology ❖Pharmacovigilance, also known as drug safety, is basically concerned with safety and efficacy of therapeutic drugs, biologicals or devices and deals with surveillance of adverse effects caused thereof. ❖An adverse effect can be defined as any unintended reaction that occurs in a patient’s body due to the administration of the drug. It could sometimes be a life-threatening event that leads to hospitalization, permanent damage or even the death of the patient. Drugs should be continuously monitored for adverse effects and the detected effects, if any, should be reported to health authorities mandatorily on a regular basis. 18 Sub-divisions of Pharmacology ❖Pharmacoepidemiology: It is a combination of clinical pharmacology and epidemiology. It deals with the study of the use and effects of drugs in large populations across the world during the post-marketing phase. In short, pharmacoepidemiology is nothing but pharmacovigilance that happens in the post marketing surveillance phase. It gives an assessment of uses as well as risks that arise from the use of drugs. ❖Pharmacovigilance and pharmacoepidemiology together play an influential part in minimizing the adverse reactions and ensure the safety and efficacy of drugs. 19 Sub-divisions of Pharmacology ❖Pharmacogenetics is the study of genetic basis for variations in drug metabolism and response in humans. It deals with identifying inherited variations through single gene i.e., G6PD deficiency, succinylcholine apnoea, StevensJohnson syndrome or epidermal toxic necrolysis, clopidogrel resistance, malignant hyperthermia, warfarin sensitivity and its resistance ❖Pharmacogenomics: This recent term overlaps with pharmacogenetics, describing the use of genetic information to guide the choice of drug therapy on an individual basis. This may help in the development of target specific personalized drugs. 20 Sub-divisions of Pharmacology ❖Pharmacoeconomics: It is the analysis of the cost of drug therapy and its benefits to the health care system and the society. It examines the quantitative relations between the cost and the benefit (cost-benefit analysis) ❖Pharmacometrics: It deals with evolving quantitative relationship between exposure to the drug (PK) and its response (PD), derived by constructing mathematical models based on few observations. Such models are used in simulations (PKPD modelling) to predict the response or a dose for patient with renal dysfunction or having undesirable effect to a given dose. 21 What is a drug ❖Definition: A ‘drug’ derived from the word ‘Drogue’ (dry herb) is a chemical substance used for the treatment, cure, prevention or diagnosis of a disease in human beings or animals. ❖This definition is incomplete due to the following reasons: It ignores the use of contraceptives which alter physiological system to prevent pregnancy, which is not a disease. The definition also fails to recognize general anaesthetics as drugs as these substances are not used for any prevention, diagnosis or cure of a disease. Similarly, vaccines or antisera which alter the pathological state by formation of antibodies are also not properly covered by this definition. ❖Therefore, WHO scientific group had modified the definition of drug as: “ any substance or product that is used or intended to be used to modify or explore the physiological system or pathological state in the benefit of the recipient.” 22 Prototype Drug ❖A prototype drug is an individual drug that represents a drug classa group of medications having similar chemical structures, mechanism of action and adverse effects. ❖Prototypes are the most important, and typically the first developed drugs within the class, and are used as a reference to which all other drugs are compared. Examples: Morphine is prototype drug for narcotic or opioid analgesic. Propranolol is prototype for beta-blockers Chlorpromazine is prototypical of phenothiazine antipsychotic Diazepam is prototype for benzodiazepines Aspirin is prototype for non-steroidal anti-inflammatory drugs. 23 Non-prescription (OTC) & Prescription Drugs ❖Non-prescription (OTC) drugs: These are safe drugs and can be sold over the counter (OTC), by the chemist without a prescription, e.g.., vitamins, antacids and paracetamol etc. ❖Prescription drugs: Classified under various schedules and drug acts. Used under medical supervision. Dispensed by an order of a registered medical practitioner Examples: antibiotics, anxiolytics, antidepressants, antidiabetics and antihypertensive drugs etc. 24 Sources of Drugs ❖Synthetic: Majority of drugs used presently are synthetic or semisynthetic and manufactured in the laboratory. Some of the drugs which were earlier obtained from plants and animals are today synthesized in the laboratory. Advantages: quality can be better controlled the process is easier and cheaper the chemical structure of the prototype drug can be modified in search of better, more potent and safer drugs Examples: Aspirin, paracetamol, metronidazole, chlorpromazine, amphetamine, chloroquine, sulphonamides, anticancer drugs etc. 25 Sources of Drugs ❖Plant source Alkaloids – Atropine from Atropa belladonna, quinine from Cinchona bark, morphine from Papverum somniferum (poppy), reserpine from Rauwolfia serpentina and nicotine from tobacco leaves. The names of all alkaloids end with ‘ne’ Glycosides- Digoxin from Digitalis purpurea Phytoestrogens from soy preparations Oils- Essential or volatile oils mainly used as carminatives, astringents in mouth washes or as flavoring agents. Examples: eucalyptus oil, clove oil, peppermint oil and ginger oil. 26 Sources of Drugs ❖Animal: Heparin, gonadotrophins, insulin, thyroxine, vitamins, vaccines and sera ❖Mineral: Liquid paraffin, magnesium sulphate, kaolin and aluminum trisilicate, radioactive iodine etc. ❖Microorganisms: Fungi, moulds and bacteria are important sources of many life saving drugs i.e., Penicillin from Penicillium notatum, chloramphenicol from Streptomyces venezuelae, griseofulvin from Penicillium griseofulvum and aminoglycoside group of antibiotics, like streptomycin from Streptomyces griseus and neomycin from Streptomyces fradiae. ❖Genetic engineering: Manipulation of genetic material using recombinant DNA technology i.e., human insulin, hepatitis B vaccine, human erythropoietin etc. 27 Essential drugs ❖World Health Organization (WHO) introduced the concept of essential medicines in 1977. ❖ Essential medicines are those that satisfy the priority health care needs of the population and are intended to be always available within the context of functioning health systems in adequate amounts, in the appropriate dosage forms, with assured quality and adequate information, and at a price the individual and the community can afford. They are selected with due regard to public health relevance, evidence on efficacy and safety, and comparative cost-effectiveness. The implementation of the concept of essential medicines is intended to be flexible and adaptable to many different situations; exactly which medicines are regarded as essential remains a national responsibility. Experience has shown that careful selection of a limited range of essential medicines results in a higher quality of care, better management of medicines (including improved quality of prescribed medicines), and a more cost-effective use of available health resources. 28 Essential drugs The WHO has developed the first essential medicines list in 1977 and since then the list has been revised every 2 years and the latest one is 21st edition developed in 2019. The essential medicine list contains limited cost-effective and safe medicines, while the open pharmaceutical market is flooded with large number of medicines many of which are of doubtful value. The model list of WHO serves as a guide for the development of national and institutional essential medicine list. The concept of essential medicines has been worldwide accepted as a powerful tool to promote health equity and its impact is remarkable as the essential medicines are proved to be one of the most cost-effective elements in health care. 29 Orphan Drugs ❖Definition: The drugs that are used for the diagnosis, treatment or prevention of rare diseases also called orphan diseases.. The expenses incurred during the development, manufacturing and marketing of the drug can not be recovered by the pharmaceutical company by selling the drugs. Governments or other philanthropic organizations can help in the development of these drugs. Examples of orphan drugs: sodium nitrite, fomepizole, liposomal amphotericin B, rifabutin, somatropin, digoxin immune Fab (digoxin antibody), liothyronine (T3) and many more. 30 Drug Nomenclature ❖ A drug is given three names and each of these names is used for different purposes. ❖ These names are: i) Chemical name, ii) Generic name or non-proprietary name or official name iii) Brand name or trade name Manipal University College Malaysia 31 Chemical Name Every drug is given a chemical name which is a precise description of its chemical constituents and indicates the arrangement and position of atoms or atomic groups (structure of the drug) This is according to IUPAC (International Union of Pure and Applied Chemistry) Chemical names are long and too cumbersome to remember. For example, Sodium [2 [(2,6dichlorophenyl)amino]phenyl]acetate is the chemical name of diclofenac sodium, a common Nonsteroidal anti-inflammatory drug (NSAID). Acetyl salicylic acid is the chemical name of aspirin Because of this complexity, they are rarely used practically when prescribing except for the very simplest compounds like sodium bicarbonate, magnesium trisilicate etc. The chemical name is important to chemists, pharmacists, and researchers who work with drugs at the chemical level. Sometimes the code name is used by the pharmaceutical company while developing the drug. 32 Generic Name Drugs are also known by generic, non- proprietary or official names. This is the name given to a drug after it might have been found to be of therapeutic use. It is approved officially by an authorized body and is same all over the world. All member nations of the World Health Organization (WHO) signed an agreement to use a single recommended International Non-proprietary Name (rINN) for each drug. It is the name with which the drug is described in official books of reference like pharmacopoeias, textbooks etc. The generic names are easier to read and pronounce than chemical names. The generic name should be used while prescribing a drug. Examples are Paracetamol, Aspirin, Diclofenac, Ciprofloxacin, Atorvastatin. Some generic names may be country specific. 33 Differences in generic names United States United Kingdom Acetaminophen Paracetamol Albuterol Salbutamol Epinephrine Adrenaline Ergonovine Ergometrine Isoproterenol Isoprenaline Meperidine Pethidine Norepinephrine Noradrenaline Lignocaine Lidocaine 34 Proprietary or brand or trade name ❖The brand (also known as proprietary or trade name) is the name given to a drug by its manufacturer. ❖A drug may have several brand names, depending on the number of manufacturers. ❖For example, diclofenac sodium is marketed under various brand names like Voltaren SR®, Dicloran®, Diclocare®, Cofenac®, etc. NOTE: The use of generic names is now more firmly established as being more ethical and freeing the medical profession from commercial ties. 35 Branded drugs vs Generic drugs 36 THANK YOU Manipal University College Malaysia (MUCM) 37