Limited information indicates that maternal doses of perphenazine up to 24 mg daily produce low levels in milk. Very limited long-term follow-up data indicate no adverse developmental effects when other phenothiazines are used alone. Monitor the infant for excessive drowsiness during breastfeeding and for developmental milestones, especially if other antipsychotics are used concurrently.

The authors describe a 26-year-old woman who became hypomanic after awakening from a semicomatose state induced by an overdose of amitriptyline-perphenazine (Triavil). She had been depressed and had a strong family history of manic-depressive illness. The case is reported to support previous evidence that dopamine is a mediator for mania.