Cyclobenzaprine and Isoniazid interaction
Cyclobenzaprine and Isoniazid: the Cyclobenzaprine prescribing label 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 Cyclobenzaprine (TONMYA) label · effective 2026-08-14
Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after discontinuation of a MAO inhibitor.
Hyperpyretic crisis seizures and deaths have occurred in patients who received cyclobenzaprine (or structurally similar tricyclic antidepressants) concomitantly with MAO inhibitors drugs.
Concomitant use of monoamine oxidase (MAO) inhibitors or within 14 days after their discontinuation ( 4 )
The concomitant use of TONMYA with MAO inhibitors is contraindicated [see Contraindications (4) ] .
Based on its structural similarity to TCAs, concomitant use of TONMYA with: MAO inhibitors may be life-threatening [see Contraindications (4) ] , Alcohol, barbiturates, and other CNS depressants may increase the risk of adverse reactions associated with these drugs, Tramadol may increase the seizure risk, Guanethidine or other similar acting drugs may block the…
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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.