Fluconazole is generally well tolerated, but there is no such thing as a drug which never has side effects. Concern about liver injury is exaggerated, since this complication seems quite rare, and usually occurs in people who are taking other medications as well, and who have taken fluconazole for months or longer, and who have immune deficiencies. But it is a possibility that needs to be kept in mind. Vomiting, diarrhea, abdominal pain and skin rashes are the most common side effects. These are not usually severe, and only occasionally is it necessary to stop the medication because of these side effects.
Allergic reactions are possible but uncommon.
Call immediately if you have any concerns. It is thus superior to ketoconazole, which gets into the milk in only tiny amounts. The baby will obviously get some, but this drug is now being promoted for use in babies for the treatment of simple thrush. There have been no complications in the baby reported from exposure to fluconazole in the breastmilk. Continue breastfeeding while taking fluconazole, though you may be told you cannot.