Suvorexant and Tizanidine interaction

Suvorexant and Tizanidine: 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 Suvorexant (BELSOMRA) label · effective 2025-03-10

Moderate

CNS Depressant Effects and Daytime Impairment: Risk of impaired alertness and motor coordination, including impaired driving; risk increases with dose; caution patients taking 20 mg against next-day driving and other activities requiring complete mental alertness ( 5.1 ).

Warnings and precautionsby drug classView label on DailyMed
Moderate

Prescribers should monitor for somnolence and CNS depressant effects, but impairment can occur in the absence of symptoms, and may not be reliably detected by ordinary clinical exam (i.e., less than formal testing of daytime wakefulness and/or psychomotor performance).

Warnings and precautionsby drug classView label on DailyMed
Moderate

Co-administration with other CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants, alcohol) increases the risk of CNS depression.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Dosage adjustments of BELSOMRA and of concomitant CNS depressants may be necessary when administered together because of potentially additive effects.

Warnings and precautionsby drug classView label on DailyMed
Moderate

The risk of next-day impairment, including impaired driving, is increased if BELSOMRA is taken with less than a full night of sleep remaining, if a higher than the recommended dose is taken, if co-administered with other CNS depressants, or if co-administered with other drugs that increase blood levels of BELSOMRA.

Warnings and precautionsby drug classView label on DailyMed

From the Tizanidine (Zanaflex) label · effective 2026-01-02

Moderate

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 )

Warnings and precautionsby drug classView label on DailyMed
Moderate

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 )] .

Warnings and precautionsby drug classView label on DailyMed
Moderate

Monitor patients who take Zanaflex with another CNS depressant for symptoms of excess sedation.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Alcohol and Other CNS Depressants Alcohol increases the exposure of tizanidine after administration of Zanaflex.

Drug interactionsby drug classView label on DailyMed
Moderate

Concomitant use of Zanaflex with CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may cause additive CNS depressant effects, including sedation.

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.