1 / 42

Pharmacology: PVN 106E

Pharmacology: PVN 106E. Chapter 1. Drugs and Factors Affecting Their Action. History of Pharmacology. Plants – original pharmacy Egypt: ancient remedies from over 3,000 years ago Hippocrates: natural laws to understand health and disease

river
Download Presentation

Pharmacology: PVN 106E

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pharmacology: PVN106E

  2. Chapter 1 Drugs and Factors Affecting Their Action

  3. History of Pharmacology • Plants – original pharmacy • Egypt: ancient remedies from over 3,000 years ago • Hippocrates: natural laws to understand health and disease • Various other scientists studied throughout the centuries • We now have thousands of drugs available with more being developed all the time

  4. Key Terms • Pharmacology • Pharmacodynamics • Pharmacokinetics • Pharmacotherapeutics • Pharmacognosy • Toxicology

  5. Pharmacology • Study of the history, sources, and physical and chemical properties of drugs • Looks at the ways in which drugs affect living systems • Various subdivisions of pharmacology have evolved

  6. Pharmacodynamics • Study of the biochemical and physiological effects of drugs • Study of drugs’ mechanisms of action

  7. Pharmacokinetics • Study of the absorption, distribution, metabolism, and excretion of drugs • This is drug card info

  8. Pharmacotherapeutics • Study of how drugs may best be used in the treatment of illnesses • Which drug would be most appropriate to use for a specific disease at what dose, etc.

  9. Pharmacognosy • Study of drugs derived from herbal and other natural (plant and animal) drug sources • Studying compositions of natural substances helps to gain knowledge for developing synthetic versions

  10. Toxicology • Study of poisons and poisonings • All drugs have the potential to become toxic

  11. Sources of Drugs • Natural • Semisynthetic • Synthetic • Biotechnology

  12. Drug Uses • Treatment of symptoms (pain relievers)‏ • Preventative drugs (vaccines)‏ • Diagnostic drugs (dyes)‏ • Cure (antibiotics)‏ • Health maintenance (insulin)‏ • Contraceptives (birth control)‏

  13. Dosage Forms • Tablets • Time released tablets • Capsules (useful for liquids) • Troches or lozenges • Suppositories • Solutions • Suspensions • Emulsions • Topicals • Implants • Parenteral products

  14. Common medication routes • Intravenous or IV – injected into a vein • Intramuscular or IM – injected into a muscle • Intradermal – injected under the skin • Subcutaneous or SQ – injected into fatty tissue • Oral or PO – by mouth

  15. U.S. Drug Legislation • Pure Food and Drug Act of 1906 - Required all drugs to meet minimal standards • Federal Food, Drug, and Cosmetic Act of 1938 - Required the drug to be safe before being distributed over state lines

  16. U.S. Drug Legislation • Comprehensive Drug Abuse Prevention and Control Act 1970 - Also known as Controlled Substance Act which classified drugs according to their abuse potential - Regulates the manufacture and distribution of drugs causing dependence

  17. Controlled substances schedule

  18. Drug Classification • As a result of legislation, four general drug categories were identified: 1. Prescription drugs 2. Non-prescription drugs (over the counter or OTC)‏ 3. Investigational drugs - Drugs being tested under the FDA 4. Illicit or “street” drugs

  19. Drug Information Resources • The Physicians Desk Reference (PDR)‏ • The American Drug Index • Drug Facts and Comparisons • The Handbook of Non-prescription Drugs • Drug Interactions • The Product Insert • The Pharmacist • Nursing Drug Guides • Formulary

  20. Physicians Desk Reference (PDR)‏ • An annual publication containing several types of drug information including appearance and chemical properties of drugs. Primarily used by prescribers (physicians, nurse practitioners, etc.)‏ • The PDR can be a good reference book, but it does not provide nursing implications. Nurses may find that specific nursing drug guides are more helpful for everyday use.

  21. The Product Insert • A detailed description • Approved by the FDA • Categories - Brand name - Generic name - Description - Clinical Pharmacology - Contraindications - Warnings - Precautions - Over dosage - Dosage and administration - How supplied

  22. Drug Names • Chemical name - The drugs chemical composition and molecular structure • Generic name (non-proprietary name)‏ - Name given by the United States Adopted Names Council - Allows the drug to be marketed

  23. Drug Names • Brand name - Also called trade name (proprietary name)‏ - The drug has a registered trademark; use of the name is restricted by the drug’s owner (usually the manufacturer)‏ for life of patent – usually 17 years - Allows the drug to be commercially distributed - The superscript ® is registered by the U.S. Patent Office and approved by the Food and Drug Administration (FDA)‏

  24. Examples of Drug Names • Chemical name ٠(+/-)-2-(p-isobutylphenyl) propionic acid • Generic name ٠Ibuprofen • Trade or Brand name ٠Motrin or Advil

  25. Principles of Drug Action • Drugs alter existing cellular or chemical functions • Some drugs exert their action by forming a chemical bond with specific receptors within the body – referred to as a lock and key effect - Agonists: substance that interacts with receptor to produce response - Antagonists: substance preventing action of agonist

  26. Principles of Drug Action • Receptors - The better the fit, the stronger the drug’s affinity; therefore, the drug’s effect occurs at lower doses

  27. Principles of Drug Action • Primary effect - Desired or therapeutic effect of the medication • Secondary effect - All other effects produced by the drug, whether desirable or undesirable • example: Compazine’s primary effect is anti-emetic. Secondary effect is anti-psychotic

  28. Liberation • Oral administration – may require full glass of fluid to aid administration • Dissolves in the gastric or intestinal fluids

  29. Absorption • First step in the passage of a drug into the body (bloodstream)‏ • Absorption can be faster when drug is consumed with fluids as it increases rate of dissolution • Presence of food may slow absorption • Most drugs are absorbed in the small intestine • Bioavailability describes absorption efficiency

  30. Distribution • The transport of a drug in the body by the bloodstream to its site of action

  31. Metabolism • Occurs before excretion and makes drugs water soluble to be able to pass through the kidneys • Also called “biotransformation” • Metabolism occurs in the liver where liver enzymes react with the drug

  32. Elimination/Excretion • The elimination of drugs from the body - Kidneys (primary organ for excretion)‏ - Liver - Bowel

  33. Adverse Drug Reaction (ADR)‏ • ADR is the term used to describe unwanted, negative consequences associated with the use of a medication • Alternative terms are side effect and adverse effect

  34. Types of ADR’s • Allergic Reactions - Type of unpredictable ADR - Response of the Patient’s immune system to the presence of the drug - Does not occur unless the patient has been previously exposed to the drug - Response may range from mild (rash) to life threatening (anaphylaxis)‏

  35. Types of ADR’s • Drug Idiosyncrasy - Abnormal reactivity to a drug caused by genetic differences – can occur on first exposure • Drug Tolerance - Patient requires a higher dosage or more frequent administration for a therapeutic effect

  36. Types of ADR’s • Toxic Reactions - Related to dosage administered - All drugs have the capability of producing a toxic effect • Teratogenic Effect - Drug causes congenital defects – usually in first trimester

  37. Common Lab Tests to Measure Drug Action • Therapeutic levels • Tests based on what the drug is supposed to do • Examples: CBC for antibiotics or PTT for Coumadin, peak/trough for antibiotics (gentamicin)

  38. Pharmacokinetics • Half life - The time it takes for one half of the original amount of a drug to be excreted from the body • Used to maintain drug levels over a 24 hour period

  39. Factors Influencing Drug Response • Age • Weight • Gender • Disease • Route of Administration

  40. Drug Interactions • Drug-drug interaction occurs when the effects of one drug are potentiated or diminished by another drug - Example: Antacids diminish the effect of tetracycline • Drug-food interaction occurs when a specific food ingested increases or decreases the effect of a drug - Example: Grapefruit juice increases effects of calcium channel blockers

  41. Drug Incompatibilities • Drugs are chemical compounds • Can interact with each other • Most often an issue in parenteral administration when mixing solutions • Must always determine the safety of mixing solutions before giving to patients • When in doubt, give separately

  42. Herbals and Botanicals • Herbs are used by 80% of the world population • Sold in nutrition stores, major drug chains, and discount retail stores (even supermarkets)‏ • Herbals are not regulated by the FDA • Herbals are chemicals • Must assess patients use of these products as some can have interactions with prescription drugs

More Related