Cough Medicines and Antihistamines- Deadly Combination

Many over-the-counter cough medicines and antihistamines contain similar medicines.  Those who take both together are in danger of taking an excessive dose.  This can amplify the sedative effect. An amplified sensation of drowsiness can present of particular danger for those who are unaware of the sedative effect and go on to operate heavy machinery or drive a vehicle.  Even taking these before a full night's rest can still produce a groggy effect the next morning.      Medical Daily