Cisatracurium and Phenytoin interaction

Cisatracurium and Phenytoin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Cisatracurium (Cisatracurium Besylate) label · effective 2026-06-30

Moderate

Antibiotics † Local anesthetics Magnesium salts Procainamide Lithium Quinidine May prolong the neuromuscular blockade action of Cisatracurium Besylate Injection Phenytoin, Carbamazepine May increase resistance to the neuromuscular blockade action of Cisatracurium Besylate Injection resulting in shorter durations of neuromuscular blockade and infusion rate requirements…

Drug interactionsnames PhenytoinView label on DailyMed
Minor

Resistance to Neuromuscular Blockade with Certain Drugs Shorter durations of neuromuscular block may occur and Cisatracurium Besylate Injection infusion rate requirements may be higher in patients chronically administered phenytoin or carbamazepine [see Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 )] .

Warnings and precautionsnames PhenytoinView label on DailyMed
Minor

Phenytoin and Carbamazepine : May shorten duration of neuromuscular blockade.

Drug interactionsnames PhenytoinView label on DailyMed

From the Phenytoin label · effective 2024-12-24

Minor

Neuromuscular blocking agents Cisatracurium, pancuronium, rocuronium and vecuronium: resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents has occurred in patients chronically administered phenytoin.

Drug interactionsby drug classView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.