Metaraminol

Monoamine oxidase inhibitors have been reported to potentiate the action of sympathomimetic amines.

The pressor effect of metaraminol is decreased but not reversed by alpha-adrenergic blocking agents.

Metaraminol should be used with caution in patients receiving digitalis, since the combination of digitalis and sympathomimetic amines is capable of causing ectopic arrhythmic activity.

Rapidly induced hypertensive responses have been reported to cause acute pulmonary oedema, cardiac arrhythmias and arrest. Metaraminol should be used with caution in patients with cirrhosis; electrolyte levels should be adequately restored if a diuresis ensues. A fatal ventricular arrhythmia was reported in a patient with Laennec’s cirrhosis while receiving metaraminol tartrate. In several instances ventricular extrasystoles that appeared during infusion of metaraminol promptly subsided when the rate of flow was reduced.

Sympathomimetic amines may provoke a relapse in patients with a history of malaria.

There are no well-controlled studies in pregnant women. Metaraminol should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the foetus.

It is not known whether metaraminol is secreted in human milk. Because many drugs are secreted in human milk, caution should be exercised if metaraminol is given to a breastfeeding mother.

Fertility

There are no fertility data available.

None stated.

The frequency of adverse events with metaraminol has not been firmly established. Excessive therapeutic effect leading to hypertension, quickly reversible by reducing the rate of infusion, and headaches are very common.

Adverse reactions listed below are classified according to frequency and system organ class (SOC). The frequencies of adverse reactions are ranked according to the following convention: Common (≥1/100 to <1/10); Uncommon (≥1/1,000 to <1/100); Rare (≥1/10,000 to <1/1,000); Very rare (<1/10,000); Not known (cannot be estimated from the available data).

Nervous system disorders

Very common: Headache

Cardiac disorders

Not known: Palpitations; sinus tachycardia; bradycardia; ventricular tachycardia; other cardiac arrhythmias (especially in patients with myocardial infarction); fatal ventricular arrhythmia reported in Laennec’s cirrhosis.

Vascular disorders

Very Common: Hypertension

Not known: Peripheral ischaemia

Skin and Subcutaneous tissue disorders

Rare: Abscess formation; tissue necrosis; sloughing

Gastrointestinal disorders

Not known: Nausea