Pipethiaden is a benzothiepin-based drug candidate that was at one time studied as a potential preventative to reduce the frequency of recurrent migraine headaches. It also has some activity as an antihistamine acting mainly at the 5-HT2A and 5HT2C receptors. Pipethiaden is a benzothiepin-based drug candidate that was at one time studied as a potential preventative to reduce the frequency of recurrent migraine headaches. It also has some activity as an antihistamine acting mainly at the 5-HT2A and 5HT2C receptors.