Cases of severe hypersensitivity syndromes, including drug rash with eosinophilia and systemic symptoms (DRESS) and toxic epidermal necrolysis (TEN), sometimes fatal, have been reported with etravirine.
Etravirine must be immediately discontinued if severe rash or hypersensitivity reaction is suspected. Delay in stopping treatment after the onset of severe rash may result in a life-threatening reaction. Patients who have stopped treatment becuase of hypersensitivity reactions should not restart Etravirine.
MHRA Drug Safety Update Volume 3 Issue 5 December 2009