Patienter kan anses for at være opioidtolerante, hvis de tager mindst 60 mg morfin peroralt om dagen, 25 mikrogram transdermal fentanyl pr. time eller en ækvianalgetisk dosis af et andet opioid i en uge eller mere.
Patients can be considered opioid tolerant if they take at least 60 mg oral morphine per day, 25 micrograms transdermal fentanyl per hour, or an equianalgesic dose of another opioid for a week or longer.