Factors Affecting Drug Activity Chapter 11

Factors Affecting Drug Activity Human variability Adverse drug reaction Drug-drug interactions Drug-diet interactions Disease States

Human Variability Human variability in biopharmaceutics and disposition is a significant factor in the outcome of drug blood concentration-time profiles and effects. Age Gender Pregnancy Genetics Body weight Psychological effects

Human Variability Human life is a continuous process but it is usually characterized as having stages and these stages are considered as Neonate=> upto 1 month, after birth Infant=>between the ages of 1 month and 2 years Child=>between 2 and 12 years Adolescent=>between 13 and 19 years Adult=>between 20 and 70 years Elder=>older than 70 years

Adverse Drug Reactions Drugs generally produce a mixture of therapeutic=>desired and adverse=>undesired effects Common adverse drug reactions CNS effects Hepatotoxicity Hypersensitivity or allergy Gastrointestinal effects Nephrotoxicity Idiosyncrasy Hematological effects Drug dependence Teratogenicity carcinogenicity

Drug-drug interaction The administration of more than one drug at a time to a patient can cause drug-drug interaction. Can result in either increases or decreases in therapeutic effects or side effects. Additive effects occur when two drugs with similar pharmacological actions result in an effect equal to the sum of the individual effects. Synergism occurs when two drugs with similar pharmacological actions produce greater effects then the sum of the individual effects.

Drug-diet interaction When elements of ingested nutrients interact with a drug and this affects the disposition of the drug Some foods contain substances that react with certain drugs, e.g., foods containing tyramine can react with (MAO) monoamine oxidase inhibitors. Pg

Disease states Hepatic Circulatory Renal Thyroid