Benadryl, that's what I use to cut the cough, I'm sorry to deceive ya
None of my cats had any complaints, none of them had hayfever either
Drugs in powder form such as cocaine are often mixed by dealers with cheap non-intoxicating substances in order to maximise profit. The substance, usually sugar or flour, is added at the point the raw drugs are cut into smaller batches for distribution. The dilution to the end user typically goes un-noticed.
In this case, CAS is using Benadryl, a popular brand of anti-allergy hayfever tablets, and clearly his customers haven't noticed.