Sodium oxybate and Tizanidine interaction
Sodium oxybate and Tizanidine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Sodium oxybate (Xyrem) label · effective 2025-07-01
• Central Nervous System Depression Xyrem (sodium oxybate) is a CNS depressant.
Abuse or misuse of illicit GHB, either alone or in combination with other CNS depressants, is associated with CNS adverse reactions, including seizure, respiratory depression, decreases in the level of consciousness, coma, and death [see Warnings and Precautions ( 5.2 )].
Central Nervous System Depression • Xyrem is a CNS depressant, and respiratory depression can occur with Xyrem use ( 5.1 , 5.4 )
…concurrent use of Xyrem with other CNS depressants, including but not limited to opioid analgesics, benzodiazepines, sedating antidepressants or antipsychotics, sedating anti-epileptic drugs, general anesthetics, muscle relaxants, and/or illicit CNS depressants, may increase the risk of respiratory depression, hypotension, profound sedation, syncope, and death.
Abuse of illicit GHB, either alone or in combination with other CNS depressants, is associated with CNS adverse reactions, including seizure, respiratory depression, decreases in the level of consciousness, coma, and death.
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 )
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.
Monitor patients who take Zanaflex with another CNS depressant for symptoms of excess sedation [see Clinical Pharmacology ( 12.3 )] .
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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.