To the Editor.—
Two persons displayed an exaggerated hyperprolactinemic response to thiothixene hydrochloride administration. Plasma prolactin concentrations greater than 200 ng/mL were achieved.The patient was a 30-year-old woman with galactorrhea and amenorrhea of 18 months' duration following a pregnancy. One year postpartum, she was hospitalized in a psychiatric unit and was subsequently given 10 mg of thiothixene hydrochloride and 10 mg of procyclidine hydrochloride daily. Six months later, examination revealed galactorrhea. Roentgenograms of the sella, a computed tomographic scan, and visual fields were normal. Plasma concentrations of prolactin in relation to drug ingestion are shown in the Table. Thereafter, the patient was given 10 mg daily of oral fluphenazine hydrochloride. While on that regimen, she was administered 2.5 mg of intramuscular (IM) thiothixene hydrochloride; the baseline prolactin level was 35 ng/mL, and 90 minutes after injection the level was 219 ng/mL.A female nurse, whose only medication was levothyroxine