Okay to drink alcohol when on antihistamines?

It's a great idea that you're looking into whether certain substances may have the potential for problematic or undesirable results! To answer your question ? it?s best to avoid mixing alcohol and antihistamines, as they both depress the central nervous system (CNS) [2], thereby impairing your ability to coordinate physical motor movements and remain awake and conscious. Additionally, alcohol decreases the efficacy of the antihistamines and can leave you to deal with hay fever?s unpleasant symptoms for a longer period of time. Furthermore, as there are individual differences in how people tolerate and break down each substance ? when taken individually or together ? it?s difficult to determine how long you may need to wait to consume one after using the other.