Sodium Nitroprusside
Cardiac Therapy · Antihypertensive: Vasodilator
Indications
Hypertensive crisis, controlled hypotension in anaesthesia, acute or chronic heart failure.
Dosage
Adults: Hypertensive crisis: By IV infusion, initially 0.5-1.5 mcg/kg/min, then increased in steps of 500 nanograms/kg/min every 5 min within range 0.5-8 mcg/kg/min (lower doses in patients already receiving other antihypertensives); stop if response unsatisfactory with max dose in 10 min. Lower initial dose of 300 nanograms/kg/min has been used. Maintenance of blood pressure at 30-40% lower than pretreatment diastolic blood pressure, 20-400 mcg/min (lower doses for patients being treated with other antihypertensives). Controlled hypotension in surgery: By IV infusion, max 1.5 mcg/kg/min. Heart failure: By IV infusion, initially 10-15 mcg/min, increased every 5-10 min as necessary; usual range 10-200 mcg/min normally for max 3 days. Children: Not recommended.
Administration
IV: IV infusion only, use only as an infusion with 5% dextrose in water. Infusion pump required. Not for direct injection. Note: A blue colour indicates almost complete degradation & breakdown of cyanide. Solutions should be wrapped with aluminium foil or other opaque material to protect from light (do as soon as possible). Compatibility: Stable in LR. Y-site administration: Drug to Drug IV Compatibility: Amikacin, aztreonam, bumetanide, calcium gluconate, cephazolin, ceftriaxone, cimetidine, dexamethasone, diltiazem, dopamine, enalapril, epinephrine, esmolol, famotidine, fentanyl, fluconazole, furosemide, gentamicin, heparin, hydrocortisone, hydromorphone, insulin regular, labetalol, linezolid, lorazepam, magnesium sulphate, methylprednisolone, metoclopramide, midazolam, milrinone, morphine, nitroglycerin, norepinephrine, ondansetron, phenylephrine, piperacillin/tazobactam, propofol,…
Adverse Effects
Associated with over rapid reduction in blood pressure (reduce infusion rate); headache, dizziness, nausea, abdominal pain, perspiration, palpitation, anxiety, retrosternal discomfort; occasionally reduced platelet count, acute transient phlebitis.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: Severe vitamin B12 deficiency; Leber's optic atrophy; compensatory hypertension. Precautions: Hypothyroidism, hyponatraemia, ischaemic heart disease, impaired cerebral circulation, elderly; hypothermia; monitor blood pressure and blood-cyanide concentration and if treatment exceeds 3 days, also blood-thiocyanate concentration; avoid sudden withdrawal, terminate infusion over 15-30 min; protect infusion from light.
Advice to Patient
Contact prescriber immediately if there is chest pain, burning or pain at infusion site. Change position slowly to minimize dizziness.
Pharmacokinetics
Onset of action: Hypotensive effect: <2 min. Duration: Hypotensive effect: 1-10 mins. Metabolism: Nitroprusside combines with Hb to produce cyanide and cyanmethemoglobin. Cyanide detoxification occurs via rhodanese-mediated conversion of cyanide to thiocyanate. Half-life elimination: Nitroprusside, circulatory: Approx. 2 mins. Thiocyanate, elimination: Approx. 3 days (may be doubled or tripled in renal failure). Excretion: Urine (as thiocyanate).
Unlicensed Use
Children: Hypertensive emergencies: Continuous IV infusion. Neonate, 500 nanograms/kg/minute then increased in steps of 200 nanograms/kg/minute as necessary to max. 8 micrograms/kg/minute (max 4 mcg/kg/minute if used for longer than 24 hr); 1 mth-18 yr, 500 nanograms/kg/ minute then increased in steps of 200 nanograms/kg/minute as necessary to max 8 mcg/kg/minute (max 4 mcg/kg/minute if used for longer than 24 hr).
Brands with this active ingredient
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