Management of common adverse drug reactions

DEFINITION AND CLASSIFICATION Adverse drug reactions are undesirable effects that occur with the administration of medications at normal doses. They can occur as a part of the normal pharmacological profile of the particular drug (type A reactions), or they may be unrelated to the drug (type B reactions). When an adverse drug reaction occurs as a result of the pharmacological profile of the drug, it is known as a predictable effect. Predictable effects take place soon after the drug is initiated or when a medication dose is increased. Examples of drugs that exhibit predictable adverse effects include anticoagulants, which produce bleeding, cardiac glycosides, which produce cardiac dysrhythmias, and insulin, which produces hypoglycaemic coma. In most situations, adverse reactions arising from predictable effects are reversible by decreasing the dose or by changing to another drug. In other situations, however, the effect can be fatal.