Bloody urine, face and ankle swelling. Life-threatening reaction may occur. If you are allergic to any substance or drug. If you take birth control pills. Studies inconclusive on harm to unborn child.
Animal studies show fetal abnormalities.
Decide with your doctor whether drug benefits justify risk to unborn child. Child may become sensitive to penicillins and have allergic reactions to penicillin drugs. Avoid nafcillin or discontinue nursing until you finish medicine. Consult doctor for advice on maintaining milk supply. Most hazardous reactions likely to occur a few minutes after taking nafcillin.