Mucocutaneous Leishmaniasis (Espundia)

A 38-year-old man from Brazil returns to clinic after a 4-year stay in the Amazon basin. He had a self-healed cutaneous ulcer on his forearm during that stay. He now presents with progressive nasal congestion, epistaxis, and progressive destruction of the nasal septum with collapse of nasal cartilage ("tapir nose"), palatal perforation, and granulomatous ulceration extending to the oropharynx and larynx. Biopsy of the mucosal lesion shows granulomatous inflammation with sparse amastigotes (Leishman-Donovan bodies) in macrophages on Giemsa stain. The condition marked **B** in the diagram is most likely present. Which of the following is the MOST APPROPRIATE first-line treatment for this condition?