All the drugs have the potential for adverse drug reactions, a risk-benefit analysis is necessary whenever a drug is prescribed. Adverse drug reaction is an appreciably harmful or unpleasant reaction, resulting from an intervention related to the use of a medicinal product, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product. Incidence and severity of adverse drug reactions vary by patient characteristics and by drug factors.
Incidence is higher with advanced age and polypharmacy. Adverse drug reactions can be considered a form of toxicity; most commonly applied to effects of over-ingestion (accidental or intentional) or to elevated blood levels or enhanced drug effects that occur during appropriate use (eg, when drug metabolism is temporarily inhibited by a disorder or another…
