atc code a04 atc code a04 atc code a04 antiemetics and antinauseants is a therapeutic subgroup of the anatomical therapeutic chemical classification system, a system of alphanumeric codes developed by the world health organization (who) for the classification of drugs and other medical products. subgroup a04 is part of the anatomical group a alimentary tract and metabolism. atc codes a alimentary tract and metabolism a01 stomatological preparations a02 drugs for acid related disorders a03 drugs for functional gastrointestinal disorders a04 antiemetics and antinauseants a05 bile and liver therapy a06 drugs for constipation a07 antidiarrheals, intestinal anti-inflammatory/anti-infective agents a08 antiobesity preparations, excluding diet products a09 digestives, including enzymes a10 drugs used in diabetes a11 vitamins a12 mineral supplements a13 tonics a14 anabolic agents for systemic use a15 appetite stimulants a16 other alimentary tract and metabolism products a b c d g h qi j l m n p r s v codes for veterinary use (atcvet codes) can be created by placing the letter q in front of the human atc code: for example, qa04. atcvet codes without corresponding human atc codes are cited with the leading q in the following list.national issues of the atc classification may include additional codes not present in this list, which follows the who version. a04a antiemetics and antinauseants a04aa serotonin (5-ht3) antagonists a04aa01 ondansetron a04aa02 granisetron a04aa03 tropisetron a04aa04 dolasetron a04aa05 palonosetron a04aa55 palonosetron, combinations a04ad other antiemetics a04ad01 scopolamine a04ad02 cerium oxalate a04ad04 chlorobutanol a04ad05 metopimazine a04ad10 dronabinol a04ad11 nabilone a04ad12 aprepitant a04ad13 casopitant a04ad14 rolapitant a04ad51 scopolamine, combinations a04ad54 chlorobutanol, combinations qa04ad90 maropitant