Final answer:
The contraindicated medication for a breastfeeding client is C. Gentamicin (Garamycin). It is unsafe due to potential adverse effects on the baby's auditory and renal systems. Safe alternatives include certain macrolides.
Step-by-step explanation:
The medication that is contraindicated for a breastfeeding client is C. Gentamicin (Garamycin). Gentamicin falls under the category of aminoglycosides, like streptomycin and tobramycin, which can be harmful if passed through breast milk due to the potential for effects on the baby's auditory and renal systems. Safe alternatives include macrolides like azithromycin, clarithromycin, and erythromycin, which are safer during breastfeeding. Other meds to avoid are chloramphenicol, clindamycin, nitrofurantoin, rifampin, sulfonamides, and trimethoprim, including the combination of trimethoprim/sulfamethoxazole. Heparin, propylthiouracil (PTU), and diphenhydramine (Benadryl) are generally considered safe under medical guidance.