A 'Dear Healthcare Professional' letter has been issued warning of rare, but potentially fatal, allergic reactions to the anti-HIV drug etravirine (Intelence).
It is manufactured by Tibotec which issued the letter on October 19th after cases of severe rash, one of which was fatal, were reported in patients taking etravirine. The letter was issued in agreement with the European Medicines Agency (EMEA).
The drug is a non-nucleoside reverse transcriptase inhibitor (NNRTI). Results from clinical trials into its development suggested that it is very safe.
However, two types of severe reaction to etravirine have since been reported: toxic epidermal necrolysis (TEN) and drug rash with eosinophilia and systemic symptoms (DRESS).
Reported cases of these reactions developed between three and six weeks after treatment with the drug was started. In most cases, they disappeared when treatment with etravirine was stopped and therapy with corticoid-steroids was provided.
Symptoms include rash, fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis and high concentrations of a type of blood cell calls eosinophils.
Product labelling for the drug has been updated to note these rare, but very serious side-effects.
Patients who develop a severe rash whilst taking etravirine should seek immediate medical advice. If a hypersensitivity reaction to the drug is diagnosed, treatment with it should be stopped immediately.
“Delay in stopping Intelence treatment after the onset of severe rash may result in a life-threatening reaction,” warns Tibotec.
The letter also cautions that “patients who have stopped treatment due to hypersensitivity reactions should not re-start therapy with Intelence.”