Not Medical Advice: It is not advisable to drink NyQuil and Red Bull at the same time as it is potentially dangerous. Unpleasant side effects may include difficultly sleeping or restlessness, fast heartbeat and increased blood pressure.
NyQuil contains 10 percent alcohol, while Red Bull has 83 milligrams of caffeine per serving. NyQuil, is a combination medication of Dextromethorphan, Decongestants, Acetaminophen (APAP) and Antihistamines.
Please ask your doctor or your pharmacist about using these products safely.
Before your next drink, learn more about what doesn't mix well with alcohol at WebMD.