**6.2 Beta adrenergic drugs (β blockers)**

These drugs are used as second line treatment of adjunctive treatment. These reduce catecholamine response at receptor level hence this is a symptomatic treatment and not a definitive treatment. Tremulousness, palpitations, excessive sweating, eyelid retraction, and heart rate decrease; by reducing sympathetic hyperactivity which is induces by excess TH in blood. Propranolol (but not other β-adrenergic agents) may also weakly block the conversion of T4 to T3 via a mechanism independent of its effect on catecholamine signalling. Propranolol is the most widely used agent because it is relatively free from adverse effects and has a short half-life. It can be given orally in a dose of 20–60 mg every 6 or 8 h and avoided in patients with known history of bronchial asthma or COPD with respiratory problems. Hypotension with Propranolol is unusual [32].
