Taking it

The recommended oral dose of etravirine tablets is 200mg (two 100mg tablets) twice daily following a meal. Taking the drug on an empty stomach is not advised. For those who have difficulty swallowing, etravirine can be dissolved in water.

In 2008, the US manufacturer of etravirine stated that it should not be co-administered with atazanavir/ritonavir, fosamprenavir/ritonavir, or tipranavir/ritonavir. ¹ 

Since the approval of the drug, two types of severe reaction to etravirine have 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 corticosteroids 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.

In August 2009, the US Food and Drug Administration inserted a new warning to the package insert for etravirine (Intelence). It stated that severe cases of rash occurred in around 1.3% of patients in phase 3 studies of the drug and 2% of patients had to stop taking the drug due to serious rash, usually occurring in the first six weeks of treatment. In the most serious cases, patients taking etravirine developed Stevens-Johnson syndrome or other severe skin reactions in which regions of the skin blister and peel away. It is expected that a similar warning will be added to European package inserts by the European Medicines Agency.

This action was followed up in October 2009 with a 'Dear Healthcare Professional' letter from the manufacturer, warning of rare, but potentially fatal, allergic reactions to etravirine. Issuance of the letter came after a fatal case of severe rash was reported. The letter was issued in agreement with the European Medicines Agency (EMEA). 

Patients who develop a severe rash while taking etravirine were advised to seek immediate medical advice. If a hypersensitivity reaction to the drug is diagnosed, treatment with it should be stopped immediately. Patients who have stopped treatment due to hypersensitivity reactions should not re-start therapy.