Potency: measure of the strength, or concentration, of a drug required to produce a specific effect.

Prescription drug: drug for which dispensing requires a written or phone order that can only be issued by or under the direction of a licensed physician.

Receptor: specific cellular structure that a drug binds to and that produces a physiologic effect.

Side effect: drug effect other than the therapeutic effect that is usually undesirable but not harmful.

Site of action: location within the body where a drug exerts its therapeutic effect, often a specific drug receptor.

Therapeutic effect: desired drug effect to alleviate some condition or symptom of disease.

Therapeutic index (TI): ratio of the LD50 to the ED50 in animal studies.

Toxic effect: undesirable drug effect that implies drug poisoning; can be very harmful or life-threatening.

Trade name: patented proprietary name of a drug sold by a specific drug manufacturer; also referred to as the brand name.

Creatinine: a metabolite of muscle metabolism that is excreted in the urine in proportion to renal function.

Creatinine clearance: a measure of renal creatinine excretion that is used to evaluate renal function.

Drug compliance: following drug prescription directions exactly as written.

Enterohepatic recycling: the process whereby drug is eliminated from the liver/biliary tract into the Gl tract and then reabsorbed from the Gl tract back to the liver.

Geriatrics: medical specialty that deals with individuals over 65 years of age.

Mixed-function oxidase system: drug microsomal metabolizing enzymes (DMMS) that decrease with age and slow the rate of drug oxidation and metabolism.

Polypharmacy: the situation in patients whose treatment involves multiple drug prescriptions.

Solvent: liquid portion of a solution that is capable of dissolving another substance.

Solution: homogeneous mixture of two or more substances.

Solute: substance dissolved in a solvent; usually present in a lesser amount.

Acetylcholine (ach): neurotransmitter of parasympathetic (cholinergic) nerves; stimulates the cholinergic Receptor.

Adrenergic receptor: receptor located on internal organs that responds to norepinephrine and epinephrine.

Afferent nerve: transmits sensory information from peripheral organs to the brain and spinal cord (central N ervous system).

Afferent nerve: transmits sensory information from peripheral organs to the brain and spinal cord (central N ervous system).

Autonomic nervous system (ans): system of nerves that innervate smooth and cardiac muscle ( involuntary) of the internal organs and glands.

Cholinergic (muscarinic) receptor: receptor located on internal organs and glands that responds To acetylcholine.