Prophylactic oral ephedrine reduces the incidence of hypotension after subarachnoid block.

The purpose of this study was to demonstrate the efficacy of oral ephedrine in preventing hypotension following subarachnoid block. Two hundred women, ASA physical status I or II, undergoing lower abdominal surgery were randomly divided into two groups (n = 100 each). All patients were given routine oral premedication consisting of diazepam 10 mg and ranitidine 150 mg at bed time and at 90 min before surgery. In addition, Group I patients received ephedrine 30 mg, orally, 30 min before subarachnoid block was administered. Group II received only routine premedication. After starting an iv line and preloading with 10 ml.kg-1 crystalloid, patients were given 0.5% heavy bupivacaine 3.2 to 3.6 ml, depending on body weight, intrathecally. Patients with decreases in blood pressure of 20% were given ephedrine i.v., in increments, in addition to crystalloids. Despite a similar level of block (T3-T4) and i.v. fluids, the total dose of ephedrine supplement in Group I was 4.3 +/- 4.8 mg compared with 11.6 +/- 9.4 mg in Group II (P < 0.01). Also, 55 patients in Group I required intraoperative inotrope supplement compared with 83 in Group II (P < 0.01). We conclude that oral ephedrine premedication is a simple and effective way of reducing the incidence of hypotension in patients undergoing lower abdominal surgery under subarachnoid block.