Zyban (buproprion) has been discussed on Lactnet as Wellbutrin (buproprion)
previously by Jack Newman.  He stated that the drug is relatively safe for
breastfeeding according to Tom Hale.  If the mother wants to she should
breastfeed while taking the medication.
Also, Briggs (p.106b/107b) states that there were no adverse effects observed in
the infant of a mother taking the drug nor was any drug or metabolite found in
the infant's plasma.  This is an indication that accumulation did not occur.

NOTE: Zyban is the same drug (buproprion) as Wellbutrin.  Many pharmacists are
very concerned that the same chemical entity is on the market with two different
names with two different indications. The danger is that a depressed, smoking
patient could potentially end up taking Zyban and Wellbutrin.