Etravirine is a medication that manages human immunodeficiency virus type 1 (HIV-1) infection. It is part of antiretroviral therapy (ART), which uses a combination of drugs to suppress the virus. This medication lowers the amount of HIV in the blood, known as the viral load, and increases the number of CD4 cells, which are immune cells that fight infections. While etravirine does not cure HIV, it helps individuals live longer, healthier lives by controlling the virus and reducing complications.
What Etravirine Is and How It Works
Etravirine belongs to a class of antiretroviral drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs). HIV, a retrovirus, relies on an enzyme called reverse transcriptase to convert its genetic material, RNA, into DNA. This step is necessary for the virus to integrate its genetic code into the host cell’s DNA and begin replicating.
Etravirine works by binding to a specific site on the reverse transcriptase enzyme, distinct from its active site. This binding changes the enzyme’s shape, preventing it from functioning properly. By inhibiting reverse transcriptase, etravirine halts the process of viral RNA being converted into DNA, stopping the virus from multiplying.
A notable characteristic of etravirine is its flexible molecular structure. This allows it to remain effective even against some HIV strains that have developed resistance to earlier NNRTIs. This flexibility enables the drug to bind to different configurations of the reverse transcriptase enzyme, making it more difficult for the virus to evolve mutations that completely negate the drug’s effect. This mechanism provides a higher barrier to resistance compared to some other drugs in its class.
Who Takes Etravirine and How It Is Used
Etravirine is prescribed for individuals with HIV-1 strains resistant to other NNRTIs and antiretroviral medications, particularly those who have already received HIV treatment. This includes adults and pediatric patients aged 2 years and older. It is always used as part of a combination antiretroviral therapy regimen, alongside other anti-HIV drugs.
The standard oral dosage for adults is 200 mg, taken twice daily, which can be one 200 mg tablet or two 100 mg tablets. For pediatric patients aged 2 to less than 18 years and weighing at least 10 kg, the dosage is determined by body weight, ensuring it does not exceed the adult recommended dose. Take etravirine after a meal, as food significantly enhances its absorption into the body. The type of food consumed does not impact the drug’s absorption.
For individuals who have difficulty swallowing tablets, etravirine tablets can be dispersed in a small amount of water (about 5 mL) until the mixture appears milky. Add 15 mL of liquid (water, orange juice, or milk) to improve taste, but avoid warm or carbonated beverages. Consume immediately, rinsing the cup multiple times to ensure the entire dose is taken.
Managing Side Effects and Other Important Considerations
Etravirine can cause side effects, including skin rash, which sometimes appears within the first six weeks of therapy. While most rashes are mild to moderate, severe and life-threatening skin reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme, have been reported. Children younger than 18 years of age may have a higher risk of severe rash when taking etravirine with other antiretroviral medications.
Prompt medical attention is necessary if a rash develops, especially if accompanied by:
Fever
General illness
Extreme tiredness
Muscle or joint aches
Blisters in the mouth
Redness and swelling of the eyes
Liver problems can also occur. Patients should contact their healthcare provider if they experience:
Yellowing of the skin or eyes
Dark urine
Pale stools
Nausea
Vomiting
Loss of appetite
Pain in the upper right side of the stomach area
Additionally, changes in body fat distribution, such as increased fat in the upper back and neck or loss of fat from the legs, arms, and face, have been observed in some individuals taking HIV medicines, including etravirine.
Etravirine interacts with many other medications, potentially altering drug levels. For example, etravirine can decrease the levels of certain antiretroviral drugs like maraviroc and raltegravir, and it should not be taken with other NNRTIs or some boosted protease inhibitors. It is also not recommended with strong inducers of certain liver enzymes (e.g., carbamazepine, phenobarbital, phenytoin), as these can significantly reduce etravirine’s concentration and lead to treatment failure. Patients should always review their complete medication profile with their healthcare provider to avoid potential drug interactions.