[Side-effects of calcium inhibitors]

Most side-effects of calcium channel blockers are related to their pharmacological properties. This is best illustrated by the most common cardiovascular side-effects, which reflect the differences between the drugs of such a heterogeneous group. Side-effects related to excessive vasodilating activity (headache, dizziness, flushing, peripheral edema, and palpitations) are most likely with drugs such as nifedipine and other dihydropyridines, which are most active on vascular smooth muscle. Those related to depressed cardiac contraction and conduction are more likely with verapamil, whereas diltiazem is intermediate between the other two drugs. In the event of the occurrence of these adverse reactions, factors such as pharmacokinetics, galenic form, and the administration mode play a role. The pathological status of the patient also comes into play. Other less common reactions such as neuropsychic, gastrointestinal and endocrine effects and gingival hyperplasia appear as a consequence of the numerous sites of action of these molecules. Hepatic, haematological and cutaneous reactions appear to be relevant to immunological mechanisms. Therefore, most of the adverse effects of calcium channel blockers originate in the common mechanism of action of these drugs.