Dextromethorphan and quinidine and Hydrocodone and chlorpheniramine interaction
Dextromethorphan and quinidine and Hydrocodone and chlorpheniramine: 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 Hydrocodone and chlorpheniramine (Hydrocodone Polistirex and Chlorpheniramine Polistirex extended-release) label · effective 2025-06-26
Serotonergic drugs : Concomitant use may result in serotonin syndrome.
Avoid the use of Hydrocodone Polistirex and Chlorpheniramine Polistirex while taking a CYP3A4 or CYP2D6 inhibitor.
Serotonergic Drugs The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
From the Dextromethorphan and quinidine (Nuedexta) label · effective 2026-01-22
Anticholinergic effects of quinidine: Monitor for worsening in myasthenia gravis and other sensitive conditions.
Anticholinergic Effects of Q uinidine Monitor for worsening clinical condition in myasthenia gravis and other conditions that may be adversely affected by anticholinergic effects.
In cases of prodrugs whose actions are mediated by the CYP2D6-produced metabolites (for example, codeine and hydrocodone, whose analgesic and antitussive effects appear to be mediated by morphine and hydromorphone, respectively), it may not be possible to achieve the desired clinical benefits in the presence of NUEDEXTA due to quinidine-mediated inhibition of…
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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.