Side effects and contraindications of beta-receptor blocking agents.

Unwanted effects of beta-receptor blocking agents can be divided into three categories: 1. Those arising specifically from the pharmacologic, i.e., beta-blocking action. 2. Side effects not directly (or not with certainty) related to beta-blockade. 3. Adverse and potentially specific reactions to individual beta-blocking agents. Category 1 covers the majority of adverse effects (heart failure, severe bradycardia and hypotension, arterial insufficiency, increased airways resistance, gastrointestinal symptoms, hypoglycemia). These can largely be avoided by proper selection and preparation of patients. Category 2 covers cutaneous reactions (rashes, alopecia, pruritus), purpura (thrombocytopenic and nonthrombocytopenic) etc. as well as side effects attributable to the central nervous system (antianxiety effects, nightmares etc.). In the third category the "oculo-cutaneous syndrome" associated with practolol is discussed.