RESUMEN
BACKGROUND: In opioid addiction tolerance occurs requiring substitution with unusually high doses. A balance must be struck between the risk of overdose with respiratory depression and QTc interval prolongation on one hand and underdosing with withdrawal syndrome on the other hand. An unreliable anamnesis can complicate adequate dosing. CASE DESCRIPTION: A 30-year-old polydrug user with a severe dependence on methadone and heroin was admitted to the Intensive Care Unit after surgery for thoracic surgery. Upon cautious initiation with methadone, severe withdrawal and pain symptoms occurred. Doubling the dose made the withdrawal symptoms disappear without signs of overdose. CONCLUSION: During hospital admission of patients with high opioid tolerance the anamnestic equivalent high opioid dose can be started immediately, provided there is a possibility of monitoring the respiration and heart rhythm. The risk of withdrawal and insufficient pain relief in a hospital is generally greater than the risk of an overdose.