METARAMINOL

Method of Administration For intravenous use. 5mg/mL Solution for Injection should not be diluted before use: it is supplied ready to use. 5mg/mL solution for injection) titrated to clinical effect. In the event of escalating vasopressor requirement, the more concentrated metaraminol 10mg/mL solution for injection or infusion can be administered as 15 – 100mg in 500 mL of infusion liquid.

When vasoactive drug support is no longer indicated, the infusion should be gradually decreased. Abrupt withdrawal can result in acute hypotension. 5mg/mL Solution for Injection in children under 12 years of age has not been established.

No data are available.

Use in the elderly:

The dosage may not require modification for elderly patients; however, geriatric patients may be more sensitive to sympathomimetic agents, therefore particular caution should be taken in this age group.

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).

System Organ Class Undesirable Effect 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. Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

There is insufficient data to recommend use in children under 12 years of age. Caution should be exercised to avoid excessive blood-pressure changes since response to treatment with metaraminol is very variable and the ensuing control of the blood pressure may prove difficult.

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.

With the prolonged action of metaraminol, a cumulative effect is possible. An excessive vasopressor response may cause a prolonged elevation of blood pressure, even after discontinuation of therapy. Metaraminol should be used with caution in cases of heart disease, hypertension, thyroid disease or diabetes mellitus because of the vasoconstrictor action.

Sympathomimetic amines may provoke a relapse in patients with a history of malaria. When vasopressor amines are used for long periods, the resulting vasoconstriction may prevent adequate expansion of circulating volume and may cause perpetuation of the shock state.

There is evidence that plasma volume may be reduced in all types of shock, and that the measurement of central venous pressure is useful in assessing the adequacy of the circulating blood volume. Blood, or plasma-volume expanders, should therefore be employed when the principal reason for hypotension of shock is decreased circulating volume.

In choosing the site for injection, it is important to avoid those areas generally recognised as being unsuitable for the use of any pressor agent and to discontinue the infusion immediately if extravasation or thrombosis occurs. Although the urgent nature of the patient's condition may force the choice of an unsuitable injection site, the preferred areas of injection should be used when possible.

1 Metaraminol Solution for Injection should not be used concurrently with cyclopropane or halothane anaesthesia, unless clinical circumstances demand it.