General Introduction to Drug Interactions

General Introduction to Drug Interactions:

·       Modification of effects of one drug, by the administration of another substance such as a drug, a nutrient (food), an herb, alcohol or tobacco smoke is termed as “Drug Interaction”.

·       The drug interaction may produce increased / decreased beneficial effects or increased adverse effects. 

·       The drug interaction which leads to undesirable effects is called as “Adverse Drug Interaction”.

·       The factors like Polypharmacy, Genetic factors, Old age, Liver or Kidney disease, other underlying diseases, Lifestyle (diet, exercise), the duration of combined therapy, Time of administration of the two substances and Therapeutic index of drugs affect the appearance of drug interactions.

Mechanisms of Drug Interactions:

v Pharmaceutical Interactions

v Pharmacokinetic interactions

·       Absorption Interactions

·       Distribution Interactions

·       Metabolism Interactions

·       Excretion Interactions

v Pharmacodynamic interactions

·       Receptor mediated Interactions

·       Non receptor mediated Interactions