The effect of magnesium sulfate concentration on the effective concentration of rocuronium, and sugammadex-mediated reversal, in isolated left phrenic nerve hemi-diaphragm preparations from the rat

Abstract

BackgroundPerioperative magnesium sulfate (MgSO4) is used for analgesic, anti-arrhythmic, and obstetric purposes. The effects of MgSO4 on the neuromuscular blockade (NMB) induced by rocuronium, and the sugammadex reversal thereof, have not been clearly quantified. We investigated the effect of various MgSO4 concentrations on the NMB by rocuronium, and sugammadex reversal, in isolated left phrenic nerve hemi-diaphragm (PNHD) preparations from the rat.MethodsRat PNHD preparations were randomly allocated to one of four groups varying in terms of MgSO4 concentration (1, 2, 3, and 4 mM, each n = 10, in Krebs solution). The train-of-four (TOF) and twitch height responses were recorded mechanomyographically. The preparations were treated with incrementally increasing doses of rocuronium and each group’s effective concentration (EC)50, EC90, and EC95 of rocuronium were calculated via nonlinear regression. Then, sugammadex was administered in doses equimolar to rocuronium. The recovery index, time to T1 height > 95% of control, and the time to a TOF ratio > 0.9 after sugammadex administration were measured.ResultsThe EC50, EC90, and EC95 of rocuronium fell significantly as the magnesium level increased. The EC50, EC90, and EC95 of rocuronium did not differ between the 3 and 4 mM groups. The recovery index, time to T1 height > 95% of control, and time to a TOF ratio > 0.9 after sugammadex administration did not differ among the four groups.ConclusionsIncreases in the magnesium concentration in rat PNHD preparations proportionally enhanced the NMB induced by rocuronium but did not affect reversal by equimolar amounts of sugammadex.

Efficacy and safety of combination of magnesium sulfate, phentolamine and nifedipine in treatment of patients with hypertensive disorder complicating pregnancy

“…It inhibits the dilatation of peripheral vessels through central inhibition, and indirectly reduces blood pressure by relieving vasospasm (6,7). However, although magnesium sulfate is clinically effective in the treatment of HDCP, it has a slow effect and its therapeutic dose greatly influences the patients' blood concentration (8,9). According to recent studies, nifedipine, a long-acting calcium antagonist, inhibits angiotensin converting enzymes and significantly lowers blood pressure, and its safety is better than that of antihypertensive drugs of the same type (10,11).…”