Cyproheptadine has fewer high-risk pharmacokinetic interactions than many psychotropics, but adds substantially to sedative and anticholinergic load and is contraindicated with MAOIs.
With: Monoamine Oxidase Inhibitors (MAOIs)
Risk: Contraindicated. Combined use may potentiate anticholinergic and CNS effects; labeling prohibits concurrent use.
Action: Avoid co-prescribing. Allow adequate washout when switching in either direction.
With: Other CNS Depressants (benzodiazepines, sedating antipsychotics, opioids, alcohol)
Risk: Additive sedation, impaired psychomotor function, increased fall and accident risk.
Action: Use lowest effective doses; counsel patients on avoiding alcohol and high-risk activities; avoid in older adults when possible.
With: Strong Anticholinergic Psychotropics (TCAs, clozapine, low-potency FGAs, paroxetine, oxybutynin, etc.)
Risk: Cumulative anticholinergic burden: constipation, urinary retention, cognitive impairment, delirium, tachycardia.
Action: Assess total anticholinergic load. Prefer non-anticholinergic alternatives if possible. Monitor bowel function, cognition, and urinary status.
With: Serotonergic Agents (SSRIs, SNRIs, MAOIs, linezolid, triptans, etc.) in Serotonin Syndrome
Risk: Cyproheptadine is used as an antiserotonergic antidote in serotonin syndrome, but should not be used to ‘mask’ ongoing serotonergic toxicity while serotonergic agents are continued.
Action: Ensure all offending serotonergic agents are discontinued in serotonin syndrome; use cyproheptadine only as adjunct with benzodiazepines and supportive care in moderate cases.
With: Hepatotoxic Drugs (valproate, isoniazid, certain antipsychotics, etc.)
Risk: Potential additive hepatic risk given rare but documented cyproheptadine hepatotoxicity.
Action: Consider baseline and periodic LFTs when combining multiple hepatotoxic agents; maintain low threshold for evaluation of hepatic symptoms.