Antipsychotic
PREGNANCY RECOMMENDATION: Limited Human Data—No Relevant Animal Data
BREASTFEEDING RECOMMENDATION: No Human Data—Potential Toxicity
PREGNANCY SUMMARY
Although occasional reports have attempted to link various phenothiazine agents with congenital malformations, most of the evidence suggests that these drugs are low risk for the embryo–fetus (see Chlorpromazine).
FETAL RISK SUMMARY
Thioridazine is a piperidyl phenothiazine. The drug is not teratogenic in animals (species not specified) (1).
Phenothiazines readily cross the placenta (2). Extrapyramidal symptoms were seen in a newborn exposed to thioridazine in utero, but the reaction was probably caused by chlorpromazine (3).
In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 63 newborns had been exposed to thioridazine during the 1st trimester (F. Rosa, personal communication, FDA, 1993). Two (3.2%) major birth defects were observed (three expected), one of which was a cardiovascular defect (one expected). No anomalies were observed in five other categories of defects (oral clefts, spina bifida, polydactyly, limb reduction defects, and hypospadias) for which specific data were available.
A case of a congenital heart defect was described in 1969 (4). However, one investigator found no anomalies in the offspring of 23 patients exposed throughout gestation to thioridazine (5). Twenty of the infants were evaluated for up to 13 years.
A brief 1993 report described a 31-year-old woman with depression, panic disorder, and migraine headaches who was exposed to a number of drugs in the first 6 weeks of pregnancy, including thioridazine, dihydroergotamine, citalopram, buspirone, and etilefrin (a sympathomimetic agent) (6). An elective abortion at 12 weeks’ gestation revealed a normal fetus.
BREASTFEEDING SUMMARY
No reports describing the use of thioridazine during human lactation have been located. It is not known if the drug is excreted into breast milk. However, other phenothiazines are present in milk and have caused toxicity (see Chlorpromazine). Sedation is a possible effect in nursing infants.
References
1.Product information. Mellaril. Sandoz Pharmaceutical Corporation, 1993.
2.Moya F, Thorndike V. Passage of drugs across the placenta. Am J Obstet Gynecol 1962;84:1778–98.
3.Hill RM, Desmond MM, Kay JL. Extrapyramidal dysfunction in an infant of a schizophrenic mother. J Pediatr 1966;69:589–95.
4.Vince DJ. Congenital malformations following phenothiazine administration during pregnancy. Can Med Assoc J 1969;100:223.
5.Scanlan FJ. The use of thioridazine (Mellaril) during the first trimester. Med J Aust 1972;1:1271–2.
6.Seifritz E, Holsboer-Trachsler E, Haberthur F, Hemmeter U, Poldinger W. Unrecognized pregnancy during citalopram treatment. Am J Psychiatry 1993;150:1428–9.