What is/are Labetalol?
Labetalol (Normodyne, Trandate) is a mixed alpha/beta adrenergic antagonist, which is used to treat high blood pressure.
Side effects may include:
- Difficulty sleeping
- Diminished sexual function
- Orthostatic hypotension (due to alpha receptor blockade)
- Scalp tingling
- Drug eruption similar to lichen planus
- A rare but potentially lethal side effect is respiratory distress.
Mechanism of action
Labetalol combines both selective, competitive, alpha-1-adrenergic blocking and nonselective, competitive, beta-adrenergic blocking activity in a single substance. In man, the ratios of alpha- to beta- blockade have been estimated to be approximately 1:3 and 1:7 following oral and intravenous (IV) administration, respectively. The principal physiologic action of labetalol is to competitively block adrenergic stimulation of β-receptors within the myocardium (β1-receptors) and within bronchial and vascular smooth muscle (β2-receptors), and α1-receptors within vascular smooth muscle. This causes a decrease in systemic arterial blood pressure and systemic vascular resistance without a substantial reduction in resting heart rate, cardiac output, or stroke volume, apparently because of its combined α- and β-adrenergic blocking activity.
This article uses material from the Wikipedia article Labetalol, which is released under the Creative Commons Attribution-Share-Alike License 3.0.