Trimeprazine tartrate, (±)10-[3-(dimethylamino)-2-methylpropyl] phenothiazine tartrate(Temaril), occurs as a white to off-white crystalline powderthat is freely soluble in water and soluble in alcohol. Its antihistaminicaction is reported to be from 1.5 to 5 times thatof promethazine. Clinical studies have shown it has a pronouncedantipruritic action that may be unrelated to itshistamine-antagonizing properties.