Psychiatric Adverse Reaction to Triple Therapy for Helicobacter Pylori : A Case of Reversible Clarithromycin-Induced Psychosis

Standard Helicobacter pylori ( H. pylori ) eradication regimens, commonly consisting of a proton pump inhibitor (PPI) combined with clarithromycin and amoxicillin, are widely regarded as safe and effective. However, clarithromycin has been rarely implicated in neuropsychiatric side effects, including acute psychosis. The onset of such adverse events can pose diagnostic dilemmas, particularly in patients without any pre-existing psychiatric history. We present a case of clarithromycin-associated transient psychosis in an otherwise healthy adult male, occurring shortly after initiation of triple therapy for H. pylori . A 35-year-old man presented with upper abdominal discomfort and was diagnosed with H. pylori -induced gastritis via upper gastrointestinal endoscopy and biopsy. He was started on standard triple therapy: clarithromycin 500 mg twice daily, amoxicillin 1 g twice daily, and pantoprazole 40 mg twice daily. Within 36 hours of starting treatment, he developed acute-onset behavioral disturbances, including paranoia, auditory hallucinations, disorganized speech, and psychomotor agitation. There was no history of psychiatric illness, substance abuse, or concurrent medication use. Laboratory evaluations, including metabolic panels, thyroid function, liver and renal parameters, were unremarkable. Computed tomography (CT) brain imaging was normal, and no signs of systemic infection were present. A provisional diagnosis of drug-induced psychosis was made. The eradication therapy was immediately discontinued, and the patient received supportive care with low-dose risperidone. Complete resolution of symptoms occurred within 48 hours of withdrawal, and the patient remained asymptomatic at 4-week follow-up. Clarithromycin is known to penetrate the blood-brain barrier and may exert neurotoxic effects through Gamma-Aminobutyric Acid (GABA) ergic modulation or proinflammatory cytokine release. Although rare, acute psychosis associated with clarithromycin has been reported in several case studies, typically with a rapid onset and full recovery following drug discontinuation. Awareness of this potential adverse effect is crucial to prevent misdiagnosis and unnecessary psychiatric treatment. Clinicians should maintain a high index of suspicion for antibiotic-induced neuropsychiatric events, especially with macrolides like clarithromycin. Early recognition and prompt withdrawal can lead to rapid recovery without long-term sequelae.