Enfuvirtide is an antiretroviral medication used in the treatment of human immunodeficiency virus type 1 (HIV-1) infection. This medication belongs to a specific class of drugs known as fusion inhibitors. Its primary role is to help manage HIV-1 infection, particularly in cases where other treatments have not been successful.
How Enfuvirtide Functions
Enfuvirtide works by preventing the HIV-1 virus from entering healthy human cells, specifically CD4+ T-cells. It achieves this by acting as a fusion inhibitor, blocking a crucial step in the viral life cycle. The virus normally binds to the host cell and then undergoes a process called fusion, where the viral envelope merges with the cell membrane, allowing the virus to enter.
This medication specifically targets a viral protein called gp41, located on the surface of the HIV-1 virus. Enfuvirtide binds to a region of gp41, preventing the necessary conformational changes that allow the viral and cellular membranes to fuse. By disrupting this fusion process, enfuvirtide effectively halts the infection at an early stage, preventing uninfected cells from becoming infected.
Clinical Use of Enfuvirtide
Enfuvirtide is prescribed for the treatment of HIV-1 infection, typically as part of a comprehensive combination therapy. It is generally reserved for adults and children weighing at least 11 kg (24 pounds) who have been previously treated with several other HIV medications. The medication is used in patients whose HIV-1 infection has not been successfully controlled by other therapies.
This drug is often considered for individuals with multi-drug resistant HIV-1, where other antiretroviral agents have failed to suppress viral replication. It acts as a “salvage therapy,” offering an option for patients with limited treatment choices due to the emergence of drug-resistant virus. While enfuvirtide helps control HIV-1, it does not provide a cure for the infection.
Administering the Medication
Enfuvirtide is administered as a subcutaneous injection. It is typically injected twice daily.
Injection sites can include the upper arm, anterior thigh, or abdomen. It is recommended to rotate injection sites to reduce soreness and prevent skin reactions. Patients should avoid injecting into areas with tattoos, scars, bruises, moles, burns, or previous injection reactions. Common reactions at the injection site include pain, redness, itching, swelling, or bruising, which are generally manageable.
Managing Potential Effects
Beyond injection site reactions, enfuvirtide can cause other potential systemic effects. Common systemic effects include nausea, diarrhea, fatigue, and insomnia. Patients may also experience muscle pain, decreased appetite, and flu-like symptoms. These effects are generally mild and may vary in intensity among individuals.
Some less common but more serious considerations warrant immediate medical attention. An increased risk of bacterial pneumonia has been reported in clinical trials, and symptoms like cough with fever, fast breathing, or shortness of breath should be reported to a healthcare provider promptly. Hypersensitivity reactions, though rare, can occur and may manifest as rash, fever, chills, hives, difficulty breathing or swallowing, and swelling of the face, eyes, lips, or mouth. Additionally, changes in the immune system, known as Immune Reconstitution Inflammatory Syndrome (IRIS), can happen as the body begins to fight previously hidden infections after starting antiretroviral therapy. Regular monitoring by a healthcare provider is important to manage these potential effects and ensure the overall safety of the treatment.