Side-effect (s) of sodium nitroprusside:

Ans. d (All of the above) (Ref. KDT Pharmacology, 6th/pg.554)NITROPRUSSIDE Toxicity:# Thiocyanate toxicity is manifested as weakness, disorientation, psychosis, muscle spasms, and convulsions, and the diagnosis is confirmed by finding serum cone >10 mg/dL. Both sodium thiosulfate and hydroxocobalamin have been advocated for prophylaxis or treatment of cyanide poisoning during nitroprusside infusion.# - Metabolic (lactic) acidosis, - Arrhythmias, - Excessive hypotension, - Methemoglobinemia.# Rarely, delayed hypothyroidism.SODIUM NITROPRUSSIDE# Sodium nitroprusside is a powerful parenterally administered vasodilator that is used in treating hypertensive emergencies as well as severe heart failure.# It dilates both arterial and venous vessels, reducing peripheral vascular resistance & venous return.# The action occurs as a result of activation of guanylyl cyclase, either via release of NO or by direct stimulation of the enzyme, resulting in raised intracellular cGMP, which relaxes vascular smooth muscle.Pharmacokinetics & Dosage# Nitroprusside is a complex of iron, cyanide groups, and a nitroso moiety.# It is rapidly metabolized by uptake into red blood cells with liberation of cyanide.# Cyanide in turn is metabolized by the mitochondrial enzyme rhodanase, in the presence of a sulfur donor, to the less toxic thiocyanate.# Thiocyanate is distributed in extracellular fluid and slowly eliminated by the kidney.# Nitroprusside rapidly lowers blood pressure, and its effects disappear within 1-10 minutes after discontinuation.# Sodium nitroprusside in aqueous solution is sensitive to light and must therefore be made up fresh before each administration and covered with opaque foil. Infusion solutions should be changed after hours.# Dosage typically begins at 0.5 microgram/kg/min and may be increased up to 10 g/kg/min.# The drug is given by intravenous infusion and arterial blood pressure monitored via intra-arterial recording.Drug ClassMechanism of actionEffectsIndicationsToxicitiesNotesAngiotensin II-receptor blockers: Losartan, CandesartanBlock angiotensin II receptorsSame as ACE inhibitorsSame as ACE inhibitorsFetal renal toxicity no coughNot as well studied as ACEIs, but seem to have same efficacyVasodilators: Nitroglycerin Nitroprusside Isosorbide dinitrate Hydralazine| nitric oxide -cGMP - vasodilationNitroclycerin, isosorbide dinitrate predominantly venodilatorsNitroprusside; dilation of arteries = veinsCHF, HTN, angina, pulmonary edemaTachycardia, headache, hypotensionNitroprusside, nitroglycerin: used in acute HF Hydralazine, isosorbide dinitrate: used in chronic HF