Interferon Beta-1a Overdose in a Multiple Sclerosis Patient

OBJECTIVE To report on a patient with multiple sclerosis (MS) who attempted suicide by taking an overdose of interferon (IFN) beta-1a. CASE SUMMARY A 38-year-old man with MS and depressive symptoms self-administered approximately 6 or 7 prefilled syringes containing 44 μg (12 MIU) of subcutaneous IFN beta-1a in a suicide attempt. Clinical examination in the emergency department revealed a modest rise in body temperature and diffuse redness of the skin of the limbs and truncal region. The patient's signs and symptoms resolved over the following 24 hours. IFN beta-1a was temporarily withdrawn and treatment with citalopram, which the patient had spontaneously discontinued before the suicide attempt, was resumed. Laboratory assessment showed no modifications in biochemical and hematologic parameters. The IFN beta-1a concentration in the serum sample taken at 48 hours after the suicide attempt confirmed that the patient had taken a very high dose of IFN. DISCUSSION Depression, a common condition in MS patients, was precipitated in this patient by the spontaneous discontinuation of citalopram and not influenced by IFN beta-1a therapy, which the patient resumed at 44 μg 3 times per week. CONCLUSIONS This case demonstrates the risks of depression in MS patients and the danger of discontinuing treatment with antidepressants. This report also shows that approximately 264–308 μg of IFN beta-1a, the highest single dose of IFN beta-1a reported taken by a human as of this writing, caused only a transient and self-limiting malaise.