About MAGNESIUM SULPHATE Saline Laxative, Osmotically acting Mechanism of Action of MAGNESIUM SULPHATE Oral: Magnesium sulfate increases peristaltic activity by causing osmotic retention of fluids, thus resulting in bowel evacuation. Parenteral: Magnesium sulfate decreases levels of acetylcholine in motor nerve terminals. It also acts on the myocardium by decreasing the rate of SA node impulse formation and prolonging the conduction time Indications for MAGNESIUM SULPHATE 1.Seizures in pregnancy 2.Hypomagnesaemia 3.Heart attack 4.Asthma 5.Constipation