Introduction to Pharmacology By Jim Clarke

Drug Naming w Chemical Name - describe chemical structure (rarely seen in medical literature) w Code Name - short letter-number combination used for experimental drugs w Generic Name - a name assigned to drug that can be used by anyone (not proprietary) w Trade Name - Proprietary name given to the drug by the manufacturer

Sources of Drug Information w BNF- “official” drug bible - not used in clinical practice except by pharmacists w PDR - prepared by drug manufacturers. Is widely available but not always thorough w Facts & Comparisons w Merck Manual - does not contain all drugs but is very clinically oriented w Various Drug “Handbooks”

Steps in Drug Approval Process w Isolation or development of new chemical w Animal studies w Investigational New Drug approval process Phase 1 - small numbers; healthy individuals Phase 2 - small numbers; subjects with disease Phase 3 - large multicenter clinical trials w New Drug Application

Abbreviations Used in Prescriptions w b.i.d.; cc; c ; gtt; h.s.; p; p.o.; p.r.n.; q; qh; q1h; q2h; q3h; q4h; q.i.d.; Px; Rx; s; ss; t.i.d.; Tx

Drug dosage forms w Oral w Injectable (parenteral) Subcutaneous Intramuscular Intravenous Spinal w Topical w Inhalational

Examples of Drugs Forms w Oral Tablet; Capsule; Pill; Liquid w Injection liquid w Topical Paste; Suppositories; Ointment; Powder w Inhalational Gas; liquid aerosol; dry powder aerosol

Metabolism of Drugs w Processes by which are transformed and deactivated Site of drug biotransformation Liver - First- Pass effect in the liver Genetic differences exist in rates of metabolism

Example of First Pass Effect

Elimination of Drug Metabolites w By the Kidney- in the urine

Concept of “Half-Life” w Time required to metobolize 1/2 of the original dose of the drug w Use of this terms helps in determining how long a drug will remain in the body

Concept of Critical Threshold w Defined as the minimum level of drug concentration needed for the desired therapeutic effect to be present.

Other Dose-related Terms w Maximal Effect: greatest response that can be produced by a drug, above which no further response can be created (sometimes called “peak effect” w Onset: how long before a drug is able to exert a therapeutic effect w Duration: how long a drug effect lasts

Agonists and Antagonists w An agonist causes a particular effect by binding to the correct “receptor”

What is an “antagonist”? w An agent that blocks are reverses the actions of another medication

Activity w Pick a commonly used drug w Find out the following: w How it is classified w What it is used for w How it is made w Route of administration w Side effects w availability