- Prohibited concomitant medications: Other members of the angiotensin receptor-blocking class (losartan, irbesartan, olmesartan, valsartan, candesartan; wash-out period allowed), nelfinavir, and etravirine. Subjects taking nelfinavir or etravirine will be excluded due to the possibility of increased drug levels via inhibition of cytochrome P-450 2C19.