Sildenafil-induced acute neuropsychiatric manifestations with cognitive impairment, affective instability, disinhibition, and hypersexuality: a case report

Sildenafil, a selective phosphodiesterase type 5 (PDE5) inhibitor, is widely prescribed for erectile dysfunction (ED) and is generally well-tolerated. Common adverse effects include headache, flushing, and dyspepsia. Although rare neuropsychiatric side effects—such as psychosis, agitation, mood disturbances, and amnesia—have been sporadically reported, to our knowledge, published reports describing this particular combination of cognitive impairment, affective instability, behavioral disinhibition, and hypersexuality following sildenafil use in a patient without a prior psychiatric history remain very limited. We describe a patient without prior psychiatric history who developed a complex, multi-domain neuropsychiatric syndrome after sildenafil exposure, with positive rechallenge and strong causality scores. We report the case of a 45-year-old man with no psychiatric history who developed acute, complex neuropsychiatric symptoms—including cognitive impairment, mixed affective features, behavioral disinhibition, and hypersexuality—following sildenafil use. Symptoms partially remitted upon drug discontinuation, recurred following re-challenge, and fully resolved with antipsychotic treatment and strict sildenafil avoidance. This case highlights sildenafil as a potential trigger of complex neuropsychiatric disturbances. Clinicians should maintain a high index of suspicion for drug-induced etiologies in patients presenting with acute atypical psychiatric symptoms.