Objective: This case report highlights the risk of Torsade de Pointes (TdP), a life threatening cardiac arrhythmia in a heroin dependent patient receiving methadone substitution therapy who was prescribed erythromycin for upper respiratory tract infection. Method: We report a case of a 35-year-old Malay man on methadone maintenance treatment who developed TdP possibly due to drug interaction between methadone and erythromycin. Results: The patient reported feeling unwell, chest pain and feeling dizzy after consuming 2 doses of erythromycin. ECG monitoring showed prolonged rate-corrected QT interval leading to TdP. The patient was admitted to the ward where the cardiac arrhythmia ceased following methadone discontinuation. This cardiac arrhythmia was most likely due to drug interaction between methadone and erythromycin (an enzyme inhibitor) which led to an increase in methadone concentration and potentiated the adverse effects. Conclusion: As methadone is a beneficial treatment for heroin dependent patients, the risk of cardiac arrhythmia is of great concern. To avoid complications of drug interaction, patients on methadone therapy should be advised to seek medical assessment before taking other drugs. As TdP is life threatening, it is thus important that physicians and psychiatrists involved in the treatment of heroin dependent patients on methadone substitution therapy be made aware of this risk.

Objective: This case report highlights the abuse and dependence potential of Zolpidem and the risk of life-threatening withdrawal symptoms upon abrupt discontinuation. Method: We report a case of Zolpidem dependence which presented with withdrawal symptoms upon abrupt discontinuation. Results: A 32 year old male, who had abused non-benzodiazepine Zolpidem for 6 years presented to the accident and emergency unit with generalized seizures upon stopping Zolpidem ‘cold turkey’. He required admission to the neurology high dependency unit for stabilization of the seizures and was later managed by the addiction team where a tapering dose of benzodiazepine was prescribed. Conclusion: This case demonstrates that non-benzodiazepine agents can cause tolerance and dependence, and thus produce withdrawal symptoms upon discontinuation.