DOXYLAMINE; VITAMIN B6 treats nausea and vomiting during pregnancy. It works by blocking substances in your body that cause nausea and vomiting. It is a combination of an antihistamine and vitamin B6. Get Doxylamine/Pyridoxine for as low as $47.72, which is 88% off the average retail price of $384.78 for the most common version, by using a GoodRx coupon.