“EFFICACY AND SAFETY OF MEPHENTERMINE, EPHEDRINE AND PHENYLEPHRINE ON POST SUBARACHNOID BLOCK INDUCED HYPOTENSION DURING LOWER SEGMENT CAESAREAN SECTION (LSCS): A RANDOMIZED, DOUBLE BLIND, PARALLEL GROUP CLINICAL TRIAL.”

H. N. Golakiya, J. B. Patel*, V. N. Naik, K. D. Nakum, D. C. Tripathi and C. B. Tripathi

ABSTRACT

Background: Lower segment caesarean section (LSCS) is commonly performed operation under subarachnoid block (SAB). Post SAB hypotension is the most common complication requiring variable doses of vasopressors to prevent detrimental consequences of hypotension to mother and fetus. Methods: This randomized, double blind, parallel group clinical trial included a total of 150 parturients undergoing emergency or elective LSCS. We compared the effect of mephentermine, ephedrine and phenylephrine immediately after the SAB. Parturients in the, mephentermine and ephedrine group received 10 mg intravenous bolus and 5 mg i.v. for maintenance; phenylephrine group received 100 μg i.v. bolus and 50 μg i.v. for maintenance. Maternal systolic and diastolic blood pressure, heart rate, fetal APGAR score, number of doses required were recorded for 3 hrs. Any episodes of adverse events were recorded. Results: We observed less changes in SBP with phenylephrine (mean diff. from baseline- MDB: 3.8 – 7.26) than mephentermine (MDB: 7.34 – 9.56) and ephedrine (MDB: 8.9 – 12.88) for initial 6 min only. We observed less changes in DBP with phenylephrine (MDB: 1.6 – 7.64) than mephentermine (MDB: 5.86 – 11.5) and ephedrine (MDB: 5.42 – 11.12) for initial 6 min only. HR decreases more significantly with phenylephrine compared to mephentermine and ephedrine (P< 0.05). Bradycardia, headache, nausea, reactionary hypertension (12%) were the side effects with phenylephrine. Conclusion: There is no clinically significant difference among mephentermine, ephedrine and phenylephrine immediately after the SAB. There was a trend for less requirement of maintenance dose with ephedrine. Phenylephrine causes fall in HR which may be advantageous in cardiac patients and in whom tachycardia is undesirable.

Keywords: Subarachnoid block, mephentermine, ephedrine, phenylephrine, hypotension, LSCS.