IV labetalol is a beta-blocker used in the treatment of serious clinical conditions such as hypertensive crisis. It may also be used to produce controlled hypotension during surgical procedures which require low blood pressure. It is used almost exclusively in specialist situations, in hospital, as it is given intravenously, or into the veins, by injection. IV labetalol may be known by different trade names in different countries, according to manufacturer and, in most countries is available by prescription only.
There are a number of different drugs belonging to the class of beta-blockers. They all work mainly by blocking the beta receptors in the body although some of them, like IV labetalol, have an effect on alpha receptors too. By blocking these receptors, the action of adrenaline and noradrenalin — the chemicals responsible for the "fight or flight" reaction — is reduced. Exerting this action on the receptors of the heart causes it to slow down which reduces the pressure with which the heart pumps, lowering blood pressure and work load on the heart.
Hypertensive crisis occurs when the blood pressure is severely increased and may be as a result of heart attack, eclampsia during pregnancy or forgetting to take antihypertensives, amongst other reasons. It should be treated as a medical emergency and immediate medical attention should be sought as stroke may result. Depending on the cause of the hypertensive crisis, a number of procedures will be followed to get the blood pressure down to a safe level.
When using IV labetalol to treat a hypertensive crisis, it is given intravenously, either at intermittent doses or as an infusion over a longer period. The dose used will depend on the severity of the hypertension and the weight of the patient. The drug is administered to the patient in a lying down position and light-headedness must be expected when the patient first stands up after administration. Usually the blood pressure will be monitored throughout treatment and dosage adjusted accordingly.
While IV labetalol is used in emergency situations on an acute basis, an oral preparation of labetalol is also available in most countries worldwide and may be used in the long-term treatment of hypertension. Both the IV and oral preparations may interact with other medications, be contraindicated in patients with some underlying clinical conditions and cause unwanted side effects in some patients. Any medications, including homeopathic, complementary and over-the-counter medications or underlying clinical conditions, such as asthma, should be discussed with the prescribing doctor.