Can intake of 50 tablets of Amosyt (dimenhydrinate) (100 mg) cause nightmares and a feeling of unre

Fråga: Can intake of 50 tablets of Amosyt (dimenhydrinate) (100 mg) cause nightmares and a feeling of unreality, as a late reaction?

A 21-year-old woman previously healthy took the tablets in combination with alcohol as an action of impulse to attempt suicide. When the patient was admitted to the hospital she was unconscious. Later on she was motorically disturbed, had hallucinations and became desoriented. She also had a seizure which was treated successfully with diazepam. The woman had a history of abuse of amphetamine and hash. The latest use of hash was four months ago.

The time after the tablet intake the patient had nightmares, was tired and had a feeling of unreality. The patient still had these symptoms 10 days after intake. The preliminary diagnosis were depression and borderline disturbance.

Sammanfattning: Hallucinations, tiredness and a feeling of unreality 10 days after a toxic dose of dimenhydrinate do not seem to be related to the intake.

Other causes may be more likely explanations to the described symptoms.

Svar: Dimenhydrinate is an anti-histamine of the older generation. Unconsciousness, hallucinations and seizures are well known acute toxic symptoms after intake of high doses (1). Experiences from case reports at The Poison Control Center tell nothing about any sequelae as described in the present case (1).

The half-life of dimenhydrinate is 5.3 hours, the volume of distribution is 3.6 liters per kilogram and the substance is excreted mainly by the kidneys (2).

Concerning the relative short half-life of the substance it may be unlikely that the intake of dimenhydrinate 10 days earlier may be an explanation to the symptoms. The use of amphetamine and hash and/or the complex psychiatric conditon may be more probable causes.

Follow up one month later: The patient is now in better condition after start of antidepressive treatment. 1 Personal communication with Gunilla Sjöberg, The Poison Control Center, Karolinska Hospital 2 Scavone JM, Luna BG, Harmatz JS, von Moltke L, Greenblatt DJ: Diphenhydramine kinetics following intravenous, oral,and sublingual dimenhydrinate administration. Biopharm Drug Disp 1990; 11: 185-189