Description: Metaraminol is a parenteral vasopressor agent. It is used to reverse or prevent hypotension that occurs with spinal anesthesia, as adjunctive therapy for hemorrhagic hypotension, for medication-induced or surgical complication of hypotension, and for shock associated with brain damage due to trauma or tumor. Metaraminol may be effective in shock associated with sepsis or cardiogenic shock. This agent is not a replacement for volume expanders (e.g., blood) in cases of hypovolemia. Metaraminol is a mixed-acting sympathomimetic amine that directly and indirectly increases peripheral resistance by producing vasoconstriction. Metaraminol is not metabolized by either COMT or MAO. This drug was approved by the FDA in 1951.
Contraindications/Precautions: Hypotension secondary to chlorpromazine, MAOIs, cardiovascular disease, hemorrhagic shock, hyperthyroidism, hypertension, malaria, sulfite hypersensitivity.
Drug Interactions:
Atomoxetine: May increase the pressor effect of metaraminol.
Guanethidine: The antihypertensive effects of guanethidine can be partially or fully reversed.
Halogenated hydrocarbon anesthetics: Can sensitize the myocardium to the effects of catecholamines.
MAOIs: Increase the pressor effect of metaraminol.
Oxytocic drugs: Can cause severe, persistent hypertension.
Tricyclic antidepressants: The pressor effects of metaraminol can be decreased.
Adverse Reactions: Anxiety, cardiac arrhythmias, hypertension, hypotension, palpitations, headache, flushing, sweating, tremors, dizziness, nausea/vomiting, tissue necrosis.
For prevention of acute hypotension:
Parenteral dosage:
Adults: 2—10 mg IM or SC. Observe patient response for at least 10 minutes before repeating dose.
Children: 100 mcg/kg or 3 mg/m[3] BSA.

For treatment of acute hypotension:
Parenteral dosage:
Adults: 15—100 mg in 250 or 500 ml of sodium chloride injection or 5% dextrose injection administered by IV infusion, with the rate adjusted according to blood pressure. In cases of severe shock, 0.5—5 mg direct IV bolus may be administered.
Severe shock: 0.5—5 mg in 500 ml NS or D5W (use caution).
Or, 2—10 mg IM.

Children: 400 mcg/kg or 12 mg/m[3] BSA as a solution containing 1 mg/25 ml NS or D5W, IV infusion given at a rate to maintain the pressure.
Severe shock: 10—300 mcg/kg or 300 mcg/m[3] BSA IV infusion (use caution).
Or, 100 mcg/kg or 3 mg/m[3] BSA IM or SC.


• cardiogenic shock
• hypotension