Background: Adding magnesium sulfate (MgSO4) to opioid receptor agonists increases the opioid analgesic
effects via blocking this receptor. The current study aimed to evaluate the effectiveness of adding MgSO4 to
tincture of opium (TOP) and buprenorphine (BUP) on pain and quality of life (QOL).
Methods: In prospective, randomized, double-blind, placebo-controlled clinical trial, one hundred and
sixty-three women with secondary dysmenorrhea caused by endometriosis were selected using a respondentdriven sampling (RDS) and assigned into six groups using block randomization. Patients received 50 mg/kg
MgSO4 in 100 ml saline by micro set in six monthly menstrual periods and completed the visual analogue
scale (VAS) and QOL Questionnaire (QOLQ). Data were analyzed by repeated measures analysis of variance
(ANOVA) and hierarchical regression.
Findings: The primary outcomes showed that pain scores in magnesium (MAG) + opium tincture (OT)
[F = 5.7(1,162), P = 0.004] and MAG+ BUP [F = 4.5(1,162), P = 0.006] groups showed a significant decrease
compared with control group. Also, QOL scores in MAG + OT [F = 4.8(1,162), P = 0.005] and MAG + BUP
[F = 5.9(1,162), P = 0.003] showed a significant increase. However, there was no significant difference
between the two groups (P = 0.140) and the changes did not persist until follow-up (P = 0.810). Secondary
outcomes indicated that the low scores of the two components of QOL including physical and psychological
components were predictors of pain (P = 0.011, Beta > 3.09).
Conclusion: Simultaneous use of MAG with opioids is associated with pain reduction and the improvement of
QOL. However, this hypothesis requires careful handling in a randomized controlled trial