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

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

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

Abbreviations Used in Prescriptions 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

Aerosolized Agents: 7 Categories Adrenergic Agents Anticholinergic Agents Mucoactive agents Corticosteroids Antiasthmatics Antiinfectives Exogenous Surfactants

Adrenergic Agents Action - stimulation of sympathetically mediated bronchorelaxation of smooth muscle Examples: Epinephrine; Isoetharine; Isoproterenol; Metaproterenol; Albuterol; Pibuterol; Bitolterol; Salmeterol

Anti-cholinergic Agents Blockage of vagally-induced bronchospasm This results in bronchorelaxation Example: Iptratroprium bromide

Mucoactive Agents Improve viscosity of mucus and enhance clearance of secretions Examples: Acetylcysteine: Dornase alpha

Corticosteroids Reduce and control inflammatory response associated with asthma and other lung diseases Examples: Dexamethasone; Beclamethasone; Triamcinolone; Flunisolide

Anti-asthmatic Agents Prevention of the inflammatory response seen in asthma by inhibition of chemical mediators necessary for inflammation to occur

Anti-infective Agents To inhibit or kill selected bacterial, protozoal, fungal or viral organisms Examples: Pentamidine; Ribavirin

Exogenous Surfactants Used by instillation in the tracheas of premature newborns suffering from respiratory distress syndrome Examples: Beractant; Colfosceril palmitate

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

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

Metabolism of Drugs Processes by which are transformed and deactivated Site of drug biotransformation Liver - cytochrome P450 pathways OR microsomal P450 pathways are used to metabolize most agents First- Pass effect in the liver Genetic differences exist in rates of metabolism

Example of First Pass Effect

Elimination of Drug Metabolites By the Kidney- in the urine

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

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

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

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

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

Hypothetical Time-Effect Curves

Concept of Potency Comparison of different drugs at the same dose to determine which is stronger

Pharmacokinetics of Inhaled Agents Tend to have local effects - at the target organ Systemic effects are usually considered side effects since they occur in organ systems other than where the drug was absorbed