Can tramadol cause auditory hallucinations?/nA 45-year-old man treated with tramadol in high doses

Fråga: Can tramadol cause auditory hallucinations? A 45-year-old man treated with tramadol in high doses (600 mg/day) because of a condition of chronic pain has reported auditory hallucinations. The patient also has a psychotic disorder but has no previous history of hearing voices. The patient also use olanzapine (Zyprexa), mirtazapine (Remeron), paracetamol (Alvedon) and melperonhydrochloride (Buronil).

Sammanfattning: Auditory hallucinations may be an adverse side effect of tramadol. However, in this specific case the underlying disease may be a confounding factor.

Svar: Tramadol hydrochloride is readily absorbed following oral administration but is subject to first-pass metabolism. Tramadol is metabolised in the liver and the metabolite O-desmethyl- tramadol is pharmacologically active. Tramadol is an opiod analgesic and it also has noradrenergic and serotonergic properties (5). Doses over 400 mg daily should not be exceeded unless there are special clinical circumstances (1).

Hallucination is a rare adverse side effect of tramadol (1,5). In the Swedish register of adverse effects there are 33 reports (out of a total of 460 reports) on tramadol and hallucinations (both vision and hearing) (2). A case report describes nightmares and hallucinations after long-term use of tramadol in combination with antidepressants (3).

Another report concerns a 74-year-old man with lung cancer who took tramadol (200 mg daily) because of pain in his chest. Soon after starting tramadol treatment he began to experience auditory hallucinations. Two days after discontinuing tramadol the hallucinations ceased (4).

We recommend this case to be reported to the regional adverse drug reaction monitoring centre.