Labetalol (Normodyne®, Trandate®, fixed combination with hydrochlorothiazide: Normozyde®) is an alpha-1 and beta adrenergic blocker used to treat high blood pressure. It works by blocking these adrenergic receptors, which slows sinus heart rate, decreases peripheral vascular resistance, and decreases cardiac output.

It has a particular indication in the treatment of pregnancy-induced hypertension.

Administration

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Labetalol is available in 100, 200, and 300 mg tablets and intravenously (only as Trandate®) in 5 mg/ml solution. Adults taking tablets usually start with 100 mg two times a day, with a maximum of 2.4 g/day. In an emergency situation, this may be higher. By IV, the patient is usually started at 2 mg/minute or 20 mg, with a maximum of 300 mg.

Side effects

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Side effects may include:

• Drowsiness
• Fatigue
• Weakness
• Difficulty sleeping
• Diminished sexual function
• Scalp tingling which passes after time.

References

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• Hodgson, Barbara B., and Kizior, Robert J. Saunders Nursing Drug Handbook 2006. St. Louis, MO: Elsevier, Saunders, 2006.