To : Dr. Walker Re : Thiothixene (Navane) Dr. Walker raised the issue as to the use of Thiothixene in a breastfeeding mother. Thiothixene is a potent member of the phenothiazine-like family of antipsychotic medications. It is structurally very similar to Chlorprothixene(Taractan). First, there is nothing published exclusively about thiothixene but there are several papers concerning others in this family including chlorprothixene (Taractan) which I have enclosed below. Most data on these family members seems to indicate that the concentration in milk is somewhat low. However, we do not know for sure the long-term outcome of infants exposed to these agents early on. So we're back to the age old question, of which is more important, the possible developmental probems in the infant, versus the known beneficial effects of breastfeeding. Further, there have been suggestions that sedatives in general, and phenothiazine neuroleptics in particular, may increase the risk of SIDS. This is still controversial. I would suggest that if this mom wants to continue to lactate, that it might be safer to convert her to Taractan which is very similar, and a medication that we have some data indicating low milk levels. This is a really tough decision. Tom Hale ------------------------------------------- Chlorprothixene Fax # 1101 Trade: Taractan Uses: Sedative, tranquilizer AAP: Not reviewed Sedative commonly used in psychotic or disturbed patients. Chlorprothixene has poor oral absorption (<40%) and has been found to increase serum prolactin levels in mothers. Although the milk:plasma ratios are relatively high, only modest levels of chlorprothixene are actually secreted into human milk. In one patient taking 200 mg/day, maximum milk concentrations of the parent and metabolite were 19 µg/L and 28.5 µg/L respectively. If an infant ingested 800 mL of milk per day, the estimated ingestion of chlorprothixene would be < 15 µg/day. This is approximately 0.1% of the maternal dose. Adverse Effects: Sedation AHL= 8-12 hours M/P= 1.2-2.6 PHL= PB = PK = 4.25 hours Oral= < 40% References: 1. Matheson I, Evang A, Fredricson OK, et.al. Presence of chlorprothixene and its metabolites in breast milk. Eur. J. Clin. Pharm. 27:611, 1984. ============================================