Chlorpromazine is detectable in the milk of some mothers during therapy, but levels appear not to correlate well with the maternal dose or serum level. Some breastfed infants become drowsy during maternal chlorpromazine therapy. Very limited long-term follow-up data indicate no adverse developmental effects when the drug is used alone. A safety scoring system finds chlorpromazine possible to use cautiously during breastfeeding.[1] However, using it in combination with haloperidol can negatively affect development. Monitor the infant for excessive drowsiness during breastfeeding and for developmental milestones, especially if other antipsychotics are used concurrently.