Allergic reactions to anticonvulsant drugs may require a change of therapy. An alternative strategy is to desensitise the patient to the offending drug. This has already been described with carbamazepine.'Oxcarbazepine is a new anticonvulsant drug developed as an alternative for patients unable to tolerate carbamazepine and sup-posedly causing fewer side-effects and allergic reactions. 2 As yet, it is only available on a named-patient basis. Sensitivity to both carbamazepine and oxcarbazepine does occur. We describe a patient successfully managed by densensitisation to oxcarbazepine. We believe this is the first reported case of successful densensitisation to oxcarbazepine. This 23 year old single man with mild mental handicap lives with his parents. He had a head injury in 1979 resulting in a post-traumatic amnesia of 24 hours. He developed complex partial seizures in 1982, but treat-ment was not started until 1983 when he had his first generalised seizure. A resting EEG was then normal. Phenytoin greatly reduced his seizure frequency but resulted in problems of slowed cognition and mild toxicity.

In 1987 he developed a psychotic illness characterised by persecutory delusions, delusions of reference and third person derogatory auditory hallucinations. He described the hallucinations as occurring episodically. He had three admissions to a local psychiatric hospital over the next 18 months but the psychotic phenomena contin-ued despite high-dose antipsychotic medication.