Adverse reactions to antihypertensive therapy.

A large number of antihypertensive agents are available today. They belong to different drug classes and permit the treating physician to choose the drug he deems best suited for the treatment of an individual patient. Because hypertension is usually asymptomatic yet requires long-term therapy, consideration of potential undesirable effects of drugs used for its treatment is important for making the appropriate choice. In this context, a precise understanding of the typical adverse reaction profiles of the different drugs is essential. This article provides a short review of the adverse reaction profiles of the main classes of antihypertensive drugs and refers to topics such as the recent controversy regarding calcium channel blockers and comparative investigations between different antihypertensive agents. Furthermore, the effects of antihypertensives on metabolic parameters, differences between their effects in subgroups of patients and in patients with different concomitant diseases, and the potential of antihypertensives for interactions with other drugs are briefly discussed. Even with a good knowledge of all of these aspects, however, no fixed plan for drug treatment of hypertension suitable for every patient can be established. A high percentage of adverse drug reactions can, however, be avoided by appropriate drug selection and dosage, carried out after careful consideration of the known adverse reaction profiles as well as the known spectrum of pharmacological actions of the different compounds. Low doses are often effective and well tolerated. Instead of increasing the dose, it is usually preferable to add a low dose of a second agent with a different mode of action if one drug given alone does not sufficiently lower blood pressure. This procedure avoids many adverse drug reactions attributable to an exaggerated pharmacological response, and, if chosen carefully, this combination may also reduce counterregulatory reactions secondary to the fall in blood pressure.