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

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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.

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