Promethazine is clinically observed to be unsafe (one report), stated to be safe in three references.

Aniemetic. The sedative effect of promethazine is lessened by caffeine. Its effect on motion sickness is enhanced by caffeine and ephedrine. ephedrine: South African list: safe EPI-list: safe Kalman, Bonkowsky: safe promethazine: South African list: use French list: authorized EPI-list: safe Shonfeld: observed to be extremely unsafe.