There appears to be no clear contraindication to the cautious use of
phenothiazines in the lowest effective dose in lactating women (monitor for
drowsiness and lethargy):
Maitra R, Menkes DB.  Psycotropic drugs and lactation.  NZ Med Journal.  June,
1996: 109 (1024); 217-9.
Thiels C. Pharmacotherapy of psychiatric disorder in pregnancy and during
breastfeeding: a review.  Pharmacopsychiatry July, 1987:  20 (4): 133-46.

Frank J. Nice, DPA, CPHP