Final answer:
Oral fluconazole is the recommended initial treatment for HIV-seropositive patients with moderate to severe oropharyngeal candidiasis.
Step-by-step explanation:
The preferred treatment option for HIV-seropositive patients with moderate to severe oropharyngeal candidiasis is oral fluconazole. Topical antifungals are commonly used for milder infections, but moderate to severe cases, particularly in immunocompromised individuals like those with HIV, often require systemic treatment. Oral fluconazole is effective in treating systemic yeast infections, including oral thrush. In cases of resistance or intolerance, other systemic azoles such as itraconazole or amphotericin B may be considered.