Drug used for hypertension and pulmonary edema due to scorpion sting:

Ans. (A) Prazosin(Ref: Harrison 20th/e p3329)Scorpion sting is a dreadful medical emergency.Scorpion stings cause a wide range of symptoms, from severe local reactions to cardiovascular, respiratory and neurological manifestations.Alpha-receptors play vital role in the pathogenesis of cardiac failure and pulmonary edema due to scorpion sting.Prazosin is a selective alpha-1 adrenergic receptor blocker. It dilates veins and arterioles, thereby reducing pre-load and left ventricular impedance without rise in heart rate and renin secretion. It also inhibits sympathetic outflow in central nervous system. It enhances insulin secretion, which is inhibited by venom action. It has also been found useful even in cases with hypotension. Thus, its pharmacological properties can antagonize the hemodynamic, hormonal and metabolic effects of scorpion venom action.