I am on three drug cocktail containing Tenofovir, Lamivudine and Nevirapine.

I have complete and absolute adherence to drug intact.

What i want to know is as how long on average that it takes for resistance to begin and develop ?

I have been on this regime for the last two years and do expect resistance to start at some point in time where a regime change will be required. So when is the earliest that resistance might show up and what is the max period that i can go on before a regime change is needed ?

Yours is a complex question. Resistance CAN develop very quickly (within a couple of weeks to a regimen such as yours). Early resistance is usually due to poor adherence. This is because the amount of medicine in the blood is too low or erratic to fully stop the virus from making copies of itself. If the virus can grow, it makes mutations (genetic changes) each time it copies itself. These mutations may enable the offspring to be able to grow in the presence of the drugs. Most drug resistance by this mechanism occurs within the first year of treatment. Unless there is a change in pattern of adherence (or a re-infection with a drug resistant virus from someone else) there is very little chance of getting resistance after that. There have been long term studies on protease inhibitors and NNRTIs that show very little drug failure due to resistance late in treatment. So, I feel your chances of staying undetectable for the foreseeable future are excellent.

Best, Joe