Sevoflurane and Tizanidine interaction
Sevoflurane and Tizanidine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Sevoflurane (Ultane) label · effective 2025-01-13
Neuromuscular Blocking Agents As is the case with other volatile anesthetics, sevoflurane increases both the intensity and duration of neuromuscular blockade induced by nondepolarizing muscle relaxants.
Therefore, during sevoflurane anesthesia, the dosage adjustments for these muscle relaxants are similar to those required with isoflurane.
In the absence of specific guidelines: For endotracheal intubation, do not reduce the dose of nondepolarizing muscle relaxants.
During maintenance of anesthesia, the required dose of nondepolarizing muscle relaxants is likely to be reduced compared to that during N 2 O/opioid anesthesia.
Administration of supplemental doses of muscle relaxants should be guided by the response to nerve stimulation.
From the Tizanidine (Zanaflex) label · effective 2026-01-02
Sedation: Zanaflex may interfere with everyday activities; sedative effects of Zanaflex, alcohol, and other central nervous system (CNS) depressants are additive ( 5.3 , 7.4 )
The CNS depressant effects of Zanaflex with alcohol and other CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants) may be additive [see Drug Interactions ( 7.4 )] .
Monitor patients who take Zanaflex with another CNS depressant for symptoms of excess sedation.
Alcohol and Other CNS Depressants Alcohol increases the exposure of tizanidine after administration of Zanaflex.
Concomitant use of Zanaflex with CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may cause additive CNS depressant effects, including sedation.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot 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.