Step 1: We are looking for an HIV drug that doubles as a hepatitis agent. Emtricitabine is an NRTI used to prevent and treat HIV in both adults and children.
Step 2: Beyond HIV, emtricitabine carries activity against the hepatitis B virus, and clinically it is paired with tenofovir for this combined coverage.
Step 3: Following the recall key, the chosen dual-purpose drug is emtricitabine.
\[\boxed{\text{Emtricitabine}}\]