INTRODUCTION TO PHARMACOLOGY
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The document discusses the importance of studying pharmacology, which is the scientific study of drugs and their interaction within biological systems. It defines key terms like pharmacology, pharmacist, drug, and outlines the major branches and concepts of pharmacology such as pharmacokinetics, pharmacodynamics, toxicology, and provides a brief history of the evolution of pharmacology from ancient to modern times.
INTRODUCTION TO PHARMACOLOGY
- 1. 1
- 2. WHY DO WE NEED TO STUDY PHARMACOLOGY? 2
- 3. Therapeutic methods • Ways to treat diseases. • Most diseases requires a combination of therapeutic methods for successful treatment. 1. Drug therapy – Txt with drugs 2. Diet therapy – Tx by diet – Low salt diet for cardio diseases 3. Physiotherapy – Tx with natural physical forces (water, light & heat) 4. Psychological therapy – Identification of stressors and methods to reduce or eliminate stress/use of drugs 3
- 4. WHAT IS PHARMACOLOGY? WHAT IS DRUG? WHAT IS THE RELATION OF PHARMACOLOGY TO NURSING? 4
- 5. Definition of Terms 5
- 6. Pharmacology • Greek word pharmakon = “drugs” • Is the scientific study of the origin, nature, chemistry, effects, and uses of drugs • deals with how drugs interact within biological systems to affect function • a branch of knowledge that has to do with the chemicals that have biological effect 6
- 7. Pharmacologist – is a scientist who specializes in the study of pharmacodynamics, employing all kinds of biochemical, physiological, and other techniques. 7
- 8. Pharmacy – is a medical science concerned with the safe and effective use of medicines. – the study of techniques involved in the preparation, compounding, dispensing, preservation and storage of the drugs for medical use. 8
- 9. Pharmacist – who is qualified and licensed – Functions: • to prepare and dispense drugs; • responsible for the manufacture of the dosage form of drugs (e.g. tablets, capsules, etc) 9
- 10. WHAT IS A DRUG? a.k.a. medications – any chemical substance which affects living systems – Dutch word “droog” means dry – used for treatment of disease, for the prevention of illness of pathologic states and for diagnosing disease condition.
- 11. What is Clinical Pharmacology? – study of drugs in humans (patient and volunteers) 11
- 12. Subdivisions/ Branches of Pharmacology What is Pharmacognosy ? • the branch of pharmacology dealing with the economic, biological and chemical aspects of natural drugs and their constituents. • study of the sources of drugs and the physical characteristics of crude or unrefined drugs. • study of drugs derived from herbal and other natural sources and how the body reacts to them. • Simply… – the study of natural (plant and animal) drug sources
- 13. Sources of Drugs Pharmacocognosy Animals Plants Minerals Synthetic Microbes 13
- 14. Sources of Drugs Pharmacocognosy Animals Products 1. Insulin =Cow and pig pancreas tissue Use to replace human chemicals not produced caused by disease/genetic problem 2. Thyroid drugs & growth hormones = animal thyroid/hypothalamus tissues 14
- 15. Sources of Drugs Pharmacocognosy Plants Important source of chemicals developed into drugs Digitalis (tx cardiac disorders) Opiates (for sedation) Marijuana •Has no legal/accepted medical use •Synthetic formed dronabinol (Marinol) active form of delta-9- tetrahydrocannabinol found in marijuana •Prevent nausea & vomiting in cancer patient but with less effect than the leaf is smoked 15
- 16. Sources of Drugs Pharmacocognosy Mineral/Inorganic Products Elements with therapeutic effects in human body Aluminum •Antacids gastric acidity •Mgt hyperphosphatemia •Prevent formation of phosphate urinary stones Fluoride Prevention of dental cavities Prevention of osteoporosis Iron Treatment of IDA Gold Tx of rheumatoid arthritis 16
- 17. Sources of Drugs Pharmacocognosy Synthetic Products Artificially produced or duplicated substances using different compounds used to be found in plants/animals/environment Benefits: 1. Drugs from the sources are produce to eliminate side effects 2. Increase potency of the drug Examples: Barbiturates, amphetamines, sulfonamides, aspirin 17
- 18. Sources of Drugs Pharmacocognosy Microbial Products •Thru genetic engineering (altering DNA) •Permits the production of human insulin by altering E.coli = less impurities than animal products 18
- 19. What is Pharmacokinetics? • The study of what the body does to the drug: 1. Absorption • movement of drug particles from the GI tract to body fluids by passive absorption, active absorption. • Movement of drug from its site of administration into the blood stream 19
- 20. What is Pharmacokinetics? • The study of what the body does to the drug: 2. Distribution • Drug molecules from BLOOD TO TISSUES 20
- 21. Pharmacokinetics • The study of what the body does to the drug: 3. Metabolism/biotransformation • drugs are inactivated by liver enzymes • Then are converted or transformed by hepatic enzymes to inactive metabolites or water-soluble substance for excretion. • Process of energy and transformation in all living cells. • Liver is the major site of drug metabolism
- 22. What is Pharmacokinetics? • The study of what the body does to the drug: 4. Excretion • elimination of drugs or its chemical byproducts • bile, feces, lungs, saliva, sweat, breast milk • Primary organ responsible for excretion is the kidney. 22
- 23. What is Pharmacodynamics ? – study of the biochemical and physiological effects of drugs as well as their mechanism of action. – Simply… • The study of what the drug does to the body – The mechanism of drug actions in living tissues 23
- 24. What is Pharmacotherapeutics ? – study of how drug may be used in the treatment of disease – which among the drugs would be most effective or appropriate for a specific disorder or what dose would be required. – Use of drugs and clinical indications of drugs to prevent and treat disease 24
- 25. What is Pharmacogenetics? – the study of genetically-determined reactions of drugs in the human body.
- 26. What is Toxicology? – study of poisonous effects of drugs 26
- 27. • Drug therapy – the proper administration of drugs used to treat disease 27
- 28. Pharmacokinetics Pharmacodynamics What the body does to drug What the drug does to body Pharmacology Pharmacotherapeutics Pharmacocognosy The study of the use of drugs Identifying crude materials as drugs Toxicology 28
- 29. • Mechanism of Action – Pharmacodynamics • Indication – the use of that drug for treating a particular disease – example: • diabetes is an indication for insulin • insulin is indicated for the treatment of diabetes • Side effect – All drugs have the potential to affect more than 1 body system simultaneously
- 30. • Adverse effect – Undesired effects that may be unpleasant or even dangerous – may occur as: 1. May have other effects on the body besides the therapeutic effect 2. Pt is sensitive to the drug given 3. Drug’s action on the body causes other responses that are undesirable/unpleasant 4. Pt taking too much/too little of the drug 30
- 31. • Tolerance – When a person begins to require higher doses to produce the same effects that lower doses once provided – Ex. Heroin addiction • Body metabolize the drug more rapidly than before 31
- 32. • Dependence – a.k.a addiction or habituation – Occurs when a person is unable to control the ingestion of drugs – Common on scheduled/controlled medications such as opiates & benzodiazepines – May be: • physical = withdrawal symptoms • Psychologic = emotionally attached to drug 32
- 33. • Cumulative effect – A drug may accumulate in the body if the next doses are administered before previously administered doses have been metabolized/excreted. – May lead to drug toxicity 33
- 34. • Over-the-counter(OTC) – Nonprescription drugs sold without a prescription in a pharmacy. • Placebo – Drug dosage form such as a tablet/capsule that has no pharmacologic activity because the dosage form has no active ingredients 34
- 35. • Half- life – The time it takes for one half of the original amount of a drug in the body to be removed – determine how often a drug needs to be given to remain in a therapeutic range 35
- 36. • First-pass effect – absorbed into the mesenteric blood system and go to the liver for biotransformation before traveling on to the general systemic circulation. – Therefore, some of the drug is inactivated and not all will be available for use at its intended site of action. 36
- 37. Brief History of Pharmacology 37
- 38. Primitive Period – Primitive people uses drugs for mystical or magic powers rather than their physiologic effect – They believed that evil spirits caused diseases – Alcohol and opium were one of the first medicinal plants 38
- 39. Ancient Period • Egypt- cradle of civilization oldest phase of medicine • Ebers Papyrus- written 3,000 years ago – an Egyptian medical source – listed 700 different remedies to treat specific ailments. – covers different prayers in driving away diseases and specific recipes for drugs (e.g. aloe, oil, opium, peppermint, and vinegar) 39
- 40. • Greece- pharmaceutical history begins with legends of gods and goddesses • Aesculapius- god of healing • Hippocrates- father of medicine • Dioscorides- – Greek physician who wrote the Materia Medica » described 600 different plants and classified them by substance rather than by the disease they intend to treat. » became the main source of pharmaceutical knowledge up to the 16th century 40
- 41. • Rome- after the Roman conquest of Greece, Greek medicine migrates to Rome Galen- a Greek physician who established a system of medicine and pharmacy -first to prepare the cold cream and rose water ointment 41
- 42. Medieval Period • Dark Age – a period of about 600 years – characterized by the destruction of old civilization and little progress in learning • There was a spread in Christianity • the establishment of the Venerable Bede – a medieval monastery where monks preserved their works on pharmacy and medicine on manuscripts 42
- 43. Medieval Period • Arabian Influence- – Establishment of schools and hospitals and discovery of many new drugs. – Arabs are the originator of syrups, alcohol, and aromatic water. – Produced the first pharmaceutical formula or set of standards (Apothecary System) • Geber – the first great Mohammedan and reputed discoverer of nitric acid, sulfuric acid, and nitrohydrochloric acid 43
- 44. Geber “Father of Arab Chemistry” 44
- 45. 16th Century • Paracelsus- “Father of Pharmacology” » Swiss scientist that first advocated the use of a single drug rather than mixtures and potions » (advantage: the dosage of a single dose can be regulated more precisely than that of complex mixtures » Improved pharmacy and therapeutics, introducing new remedies and compounds and reducing overdosing 45
- 46. 17th Century • Great interest was displayed in chemistry and pharmacy and many preparations are in use. • Ex. Cinchona bark – discovered by the Indians; used in treating and preventing malaria. • Syrup of ipecac – discovered by the natives of Brazil; used for amoebic dysentery • William Harvey – explained how drugs exert beneficial or harmful effects. – also demonstrated the circulation of blood in the body and introduced a new way of administering drug – Intravenously 46
- 47. 18th Century • Edward Jenner – an English physician who made the first public inoculation of smallpox vaccine in 1756 William Withering – an Englishman who introduced the infusion digitalis for the treatment of heart disease. 47
- 48. 19th Century • Friedrich Serturner – a German pharmacist who discovered alkaloid morphine substance. • Francois Magendie & Claude Bernard – with the use of purified drug, they demonstrated that certain drugs work at specific sites of action within the body. • The French Codex was the first important pharmacology book to be produced in 1818. • Ether and Chloroform were first used as general anesthesia in the 1840s.
- 49. 20th Century • Important legislation was instituted to control the manufacture and sales of drugs. – Food and Drug Act of 1906 & 1938 and – the Harrison Narcotic Drug Act of 1914 & – Controlled Substance Act of 1970. • Lister & Semmelweis – introduced the use of antiseptics to prevent infection during surgery • Two early landmarks in the 20th century: – Ehrlich – introduced Salvarsan for treating syphilis and responsible for the introduction of antibiotics – Banting & Best’s discovery of insulin in treating diabetes.