A driver cannot take a controlled substance or prescription medication without a prescription from a licensed practitioner.
If a driver uses a drug identified in 21 CFR 1308.11 (391.42(b)(12)) or any other substance such as amphetamine, a narcotic, or any other habit forming drug, The driver is medically unqualified.
There is an exception: the prescribing doctor can write that the driver is safe to be a commercial driver while taking the medication. In this case, the Medical Examiner may, but does not have to certify the driver.
Any anti-seizure medication used for the prevention of seizures is disqualifying.
Methadone use is disqualifying.
The Medical Examiner has 2 ways to determine if any medication a driver uses will adversely affect safe operation of a CMV:
1. Review each medication - prescription, non-prescription and supplement
2. Request a letter from the prescribing doctor