Possible Interaction: Magnesium Sulfate and Oxytocin

“There was a significant difference in the maximum dose of oxytocin used (13.9 +/- 8.6 mU/min with magnesium sulfate vs 11.0 +/- 7.6 mU/min with placebo, p = 0.036).”

“We hypothesized that MgSO4 pretreatment would reduce oxytocin-induced myometrial contractions in both oxytocin-naïve and oxytocin-desensitized myometrium.”

“ Oxytocin (0.5 nmol/L) significantly reduces the tocolytic potency of magnesium sulfate , which may explain, in part, magnesium sulfate's poor efficacy in vivo; however, this can be reversed partially by the use of an oxytocin receptor antagonist.”

“ Oxytocin reversed both the inhibited contractile force and the prolonged contractile interval caused by a high concentration of magnesium sulfate but accelerated the contractile interval and had no significant effect on the contractile force suppressed by metoclopramide.”

“ Oxytocin and Bay K 8644 increased [Ca(2+)](i) in either calcium-containing or calcium-free media, and magnesium sulfate reduced this in both cases.”

“We also report the action of MgSO4 as an inhibitory agent of [Ca2+]i increase stimulated by oxytocin.”

“These data would suggest: (1) that parenteral magnesium sulfate administration with or without concomitant oxytocin infusion may be an additional predisposing cause of acute puerperal uterine inversion and (2) that treatment with prophylactic antibiotics offers no additional benefit.”

“ Magnesium sulfate had a dose-dependent inhibitory effect on both spontaneous and oxytocin-induced contractions but was less effective in the presence of oxytocin.”

“ Magnesium sulfate had a dose-dependent inhibitory effect on both spontaneous and oxytocin-induced contractions but was less effective in the presence of oxytocin.”