Besides alcohol, what other drugs can affect a person's ability to drive safely?
If you are driving, check the label before you take a drug for warnings about its effect(s). If you are not sure whether it is safe to take the drug and drive, ask your doctor or pharmacist about any side effects. Drugs taken for headaches, colds, hay fever or other allergies, or those to calm nerves can make a person drowsy and can affect his or her driving. Other prescription drugs can affect your reflexes, judgment, vision, and alertness in ways similar to alcohol. [Drugs and Driving, Drinking and Driving, CHAPTER 3: DRIVING BEHAVIORS, Driver's Manual State of Connecticut DMV]