Indications: hypertension (including hypertension in pregnancy, hypertension with angina, and hypertension following acute myocardial infarction); hypertensive crisis; controlled hypotension in anaesthesia.

Cautions and Contra-indications: (see Propranolol Hydrochloride); interferes with laboratory tests for catecholamines; severe hepatocellular damage.

Appropriate laboratory testing needed at first symptom of liver dysfunction and if laboratory evidence of damage (or if jaundice) occurs, labetalol should be stopped and not restarted.

Side Effects: postural hypotension (avoid upright position during and for 3 hours after intravenous administration), tiredness, weakness, headache, rashes, scalp tingling, difficulty in micturition, epigastric pain, nausea, vomiting; liver damage; rarely lichenoid rash. Dose: by mouth, initially 100 mg (50mg in elderly) twice daily with food, increased at intervals of 14 days to usual dose of 200 mg twice daily; up to 800 mg daily in 2 divided doses (3-4 divided doses if higher); max. 2-4 g daily.

By intravenous injection, 50 mg over at least 1 minute, repeated after 5 minutes if necessary; max. total dose 200mg.

Note: Excessive bradycardia can be countered with intravenous injection of atropine sulphate 0.6 – 2.4 mg in divided dose of 600 mcg.

By intravenous infusion, 2 mg/minute until satisfactory response then discontinue; usual total dose 50-200 mg (not recommended for phaeochromocytoma) Hypertension of pregnancy, 20 mg/hour, doubled every 30 minutes; usual max. dose 160 mg/hour.

Hypertension following myocardial infarction, 15 mg/hour, gradually increased to max. 120 mg/hour.