Cases That Test Your Skills

The inexplicably suicidal patient

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It is not clear whether a single 25-mg dose of meclizine—an H1-receptor antagonist—played a role in Mr. A’s psychotic symptoms. Meclizine overdose can cause extreme drowsiness, seizures, hallucinations, and decreased breathing. This anticholinergic has a half-life of only 6 hours and a duration of action of up to 24 hours, although anticholinergic toxicity from overdose can last for days.10 Mr. A ingested a single 25-mg dose of meclizine, however, and his auditory hallucinations persisted for 9 days. Furthermore, Mr. A’s previous well-tolerated meclizine use and lack of other signs and symptoms of anticholinergic toxicity do not support a substantial role for meclizine in his psychotic symptoms.

OUTCOME: Symptoms resolve

Mr. A’s confusion and auditory hallucinations resolve approximately 36 hours after he completed amoxicillin treatment. When transferred to the psychiatric unit, he denies auditory hallucinations or suicidal ideation. He also denies ear pain, tinnitus, vertigo, or ear tenderness; physical examination of the ear is unremarkable. Throughout the hospital admission, Mr. A experiences no confusion or changes in mental status and he continues to adamantly deny suicidal ideation.

He does not require treatment with anti-psychotics or other psychotropic medications and is discharged in stable condition.

Related resources

  • Levenson JL, Schneider RK. Infectious diseases. In: Levenson JL, ed. The American Psychiatric Publishing textbook of psychosomatic medicine. Washington, DC: American Psychiatric Publishing; 2005:577-98.

Drug brand names

  • Amoxicillin • Amoxil, Trimox, others
  • Amphotericin B • Amphocin, Abelcet
  • Ampicillin • Principen
  • Chloramphenicol • Chloromycetin
  • Ciprofloxacin • Cipro
  • Clofazimine • Lamprene
  • Cycloserine • Seromycin
  • Ethionamide • Trecator
  • Flucytosine • Ancobon
  • Ganciclovir • Cytovene
  • Griseofulvin • Fulvicin U/F, Grifulvin V
  • Isoniazid • Nydrazid
  • Ketoconazole • Nizoral
  • Meclizine • Antivert, Bonine, others
  • Rifampin • Rifadin, Rimactane
  • Trimethoprim/sulfamethoxazole • Bactrim, Septra


The authors report no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

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