Clemastine and Metaxalone interaction
Clemastine and Metaxalone: 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 Metaxalone label · effective 2026-02-03
If concomitant use with another CNS depressant is warranted, closely monitor for signs of respiratory depression and sedation, particularly during treatment initiation and dosage increases.
If concomitant use of metaxalone and another CNS depressant is warranted, closely monitor for signs of respiratory depression and sedation, particularly during treatment initiation and dosage increases.
Depressants If concomitant use of Metaxalone Tablets, 640 mg and another CNS depressant is warranted, closely monitor for signs of respiratory depression and sedation, particularly during treatment initiation and dosage modification.
Due to the additive pharmacologic effect, concomitant use of Metaxalone Tablets, 640 mg with other CNS depressants may increase the risk of sedation and respiratory depression [see Warnings and Precautions (5.2) ].
Central Nervous System (CNS) Depression : Metaxalone Tablets, 640 mg may impair mental and/or physical abilities required for the performance of hazardous tasks, such as operating machinery or driving a motor vehicle, and may enhance the effects of other CNS depressants including alcohol.
From the Clemastine (Clemastine Fumarate) label · effective 2024-11-25
Use with CNS Depressants Clemastine has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc.). Use in Activities Requiring Mental Alertness Patients should be warned about engaging in activities requiring mental alertness such as driving a car or operating appliances, machinery, etc.
Drug Interactions Additive CNS depression may occur when antihistamines are administered concomitantly with other CNS depressants including barbiturates, tranquilizers, and alcohol.
Patients receiving antihistamines should be advised against the concurrent use of other CNS depressant drugs.
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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.