We developed an interactive voice response (IVR) system called TAMA (Treatment Advice by Mobile Alerts) that provides treatment support to people living with HIV / AIDS (PLHA) in developing countries, who are on antiret-roviral therapy (ART). We deployed TAMA with 54 PLHA in 5 HIV clinics in India for a period of 12 weeks. During the study, we gathered feedback about TAMA's design and usage. Additionally, we conducted detailed qualitative interviews and analysed usage logs. We found that TAMA was usable and viable in the real life settings of PLHA and it had many desirable effects on their treatment adherence. We developed insights that inform the design of TAMA and some of these can be generalised to design of other long-term, frequent-use IVR applications for users in developing countries in the healthcare domain and beyond.