International generic name

Sodium nitroprusside

Drug form and composition

Powder for solution for injection and solvent. One ampoule of 10 ml contains 30 mg Sodium nitroprusside (powder for solution for injection). One ampoule of 5 ml contains 5 ml Sterilised water for injections (solvent).

Indications

Hypertension crisis in following conditions: controlled hypertension during a surgery; paroxysmal hypertension during an operative extirpation of pheochromocytoma; overdosage of ergo-alkaloides. Acute heart failure, due to a myocardial infarction, cardiomyopathia, mitral and aortic valve disease. In patients with a myocardial infarction, in order to reduce the cardiac preload.

Dosage and administration

The lyophilized powder in the brown ampoule is mixed with the content of the solvent ampoule. So prepared solution is placed in a bank with 500 ml 5-10% solution of manitol, saline or 5% glycose solution. The solution is applied as a continuous intravenous infusion. In order to achieve a better dosage an infusion pump could be used; during the infusion blood pressure should be monitored. The dose should be individualized, and if necessary it is enhanced until the desired effect is achieved. Recommended initial dose is 0.3-1 mg/kg/min. Average dose is 3-4 mg/kg/min. Maximal dose in adults is 8 mg/kg/min, whereas in children it is 10 mg/kg/min. In case a hypotensive effect is not achieved within 10-15 minutes with dose 8 mg/kg/min (but no more than 500 mg/min) the infusion should be discontinued. The treatment duration usually is 10-30 hours. If the infusion is continued for more than 3 days is necessary to control the thiocyanate serum level (thiocyanate level should not exceed 6 mg/100 ml). In case the thiocyanates achieve extremely serum concentration a dialysis should be performed.

Contraindications

Naniprus is contraindicated in hypersensitivity to the preparation, patients with arterial-venous aneurysm or aortic coarctation, in increased intracranial pressure, hypotension, hypovolemia, and reduced activity of the enzyme methemoglobin-reductase.

Special warnings and precautions

In patients with severe liver function disorders, renal failure, and brain circulation disorders the dose of Naniprus should be reduced. In younger patients the treatment should be started with low dose, which is increased gradually, in order to prevent severe compensatory reactions. In patients with hypothyroidism and renal failure a long-term therapy with Naniprus may enhance the thiocyanate concentration, which inhibits iodine utilization in the thyroid gland. In pregnant women a careful assessment of the ratio benefit for the mother/risk for the fetus should be made. In case the prepared ex tempore solution changes its color to red or blue it should not be applied. As Naniprus is a highly photosensitive preparation, it should be kept away from light.

Drug interactions

Concomitant administration of ganglion-blocking agents and clonidine is not advisable. In order to enhance the hypotensive effect Naniprus could be combined with other antihypertensive agents. In patients with heart failure and reduced cardiac output Naniprus could be combined with cardiotropic preparations, like dopamine. Such a combination reduces the pulmonary capillary pressure and the myocardial oxygen consumption.

Adverse reactions

The preparation may provoke a severe hypotension, which is corrected 5 minutes after infusion discontinuation. In some patients hypersensitivity reactions may appear. In long-term treatment with the preparation following symptoms may appear: nausea; headache; dizziness; muscular spasms; dysarthria; tachycardia; psychotic reactions.

Pharmacological mechanisms

Naniprus is a powerful vasodilator. It activates the enzyme guanylate-cyclase and increases the intracellular concentration of the cGMP, inhibits the calcium and chlorine influx, relaxes the vascular muscle, reduces the arterial pressure, improves the contractile function of the heart (pre- and afterload), reduces platelet aggregation. The action of Naniprus is directed exceptionally to the vascular muscles and is realized independently to the autonomic nervous system.

Supplied

1 ampoule of 10 ml (30 mg) - powder for solution for injection, and 1 ampoule of 5 ml (solvent).

Expiry

5 years.