Ask your doctor for more information about what is relevant to you. It depends on what has been prescribed and what state you live in.
While drowsiness is not a known side effect of CBD alone, it may occur if the CBD interacts with other medications. Some medicinal cannabis products may also include tetrahydrocannabinol (THC), in which case depending on the state in which you reside, there is a strict ban on driving and operating machinery.
This link may be of help: Quick Facts: Medicinal Marijuana & Driving