1-Methyl-3-(thioxanthen-9-ylmethyl)piperidine hydrochloride monohydrate 4969-02-2 7081-40-5 Methixene hydrochloride Methixene hydrochloride [USAN] Methixene hydrochloride monohydrate NSC 78194 Piperidine, 1-methyl-3-(9H-thioxanthen-9-ylmethyl)-, hydrochloride, monohydrate SJ 1977