TREATMENT
Based on clinical history, laboratory and radiological findings, he was
diagnosed with true gynecomastia. The patient was discussed at the HIV
service’s multidisciplinary clinic and anastrozole was proposed as an
alternative to tamoxifen to avoid the possible drug-drug interaction
with rilpivirine. He was started an oral dose of anastrozole 1 mg once
daily. After 10 days from the start of anastrozole, he presented a
significant symptom improvement with visible reduction of breast
enlargement and decreased discomfort. After six weeks of use of
anastrozole, complete resolution of the gynecomastia occurred and the
patient stopped anastrozole.
In the meantime (19/05/2023), the patient referred weight gain of 3
kilograms (in a span of 11months) and opted for switching back to oral
antiretroviral treatment containing tenofovir + lamivudine + doravirine,
while he was still on anastrazole. The latter provided a benefit (versus
the most commonly used tamoxifen) with this ARV combination as well, as
a drug-drug interaction between tamoxifen and doravirine, although not
studied, may occur and again lead to a decrease in doravirine
concentrations through CYP3A4 induction9.