Effect of nicardipine on the reversal of magnesium toxicity by calcium gluconate in nonpregnant rabbits.
OBJECTIVE
To determine whether nicardipine, a dihydropyridine, inhibits the ability of calcium gluconate to reverse magnesium-induced toxicity.


METHODS
The reversal of magnesium-induced neuromuscular blockade of skeletal muscle in the presence of nicardipine was assessed using a nerve stimulator. Nicardipine (12 mg) or an equivalent volume of saline was administered intramuscularly to 19 nonpregnant rabbits in a randomized, blinded manner. Magnesium sulfate, 800 mg, was then infused intravenously in all animals, an amount sufficient to cause toxicity as measured by depression of skeletal muscle twitch and by average serum levels of 10.4 mEq/L. Calcium gluconate (300 mg) was then infused in all animals, and reversal of neuromuscular blockade was measured using the nerve stimulator to compare the saline- and nicardipine-treated groups.


RESULTS
Administration of calcium gluconate was equally effective in reversing magnesium-induced toxicity in both the control and test groups.


CONCLUSIONS
Nicardipine does not block the ability of calcium gluconate to reverse magnesium-induced neuromuscular blockade.
Department of Gynecology and Obstetrics, Stanford University School of Medicine, California.
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M
Moir
R H
RH
Holbrook
D000818:Animals; D002125:Calcium Gluconate / Q000494:pharmacology*; D003864:Depression, Chemical; D004558:Electric Stimulation; D005260:Female; D008274:Magnesium / Q000633:toxicity*; D009119:Muscle Contraction / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects; D009529:Nicardipine / Q000494:pharmacology*; D011817:Rabbits
D009529:Nicardipine; D008274:Magnesium; D002125:Calcium Gluconate