Fuzeon is administered by subcutaneous (under the skin) injection, usually twice daily. It comes as a powder that must be mixed (reconstituted) with sterile water for injection (provided in the kit) right before use.

• Preparation: You or a trained caregiver will learn how to mix the powder and water carefully to get a clear, colorless solution. It’s crucial to use strict sterile (aseptic) technique to prevent infection.
• Injection Sites: The injection should be given into the fatty tissue of the upper arm, front of the thigh, or abdomen (tummy).
• Site Rotation: It’s very important to change the injection site each time to avoid local skin reactions. Do not inject into areas with lumps, scars, moles, or where previous injections have caused reactions.
• Missed Dose: If a dose is missed, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed one and continue your regular schedule. Do not double the dose.

A healthcare professional will provide detailed training on how to prepare and inject Fuzeon properly.

Fuzeon works in a unique way to prevent the HIV virus from infecting healthy cells. HIV attacks the body’s immune cells (CD4+ cells) by first attaching to them and then “fusing” its outer layer with the cell’s outer layer to enter. Fuzeon, or enfuvirtide, acts as a “fusion inhibitor.” It binds to a specific protein on the surface of the HIV virus (called gp41). By binding to this protein, Fuzeon physically blocks the necessary steps that allow the virus to fuse with and enter human cells. This prevents the virus from getting inside healthy cells to multiply. By stopping the virus from entering new cells, Fuzeon helps reduce the amount of HIV in the body (viral load) and helps the immune system stay stronger.

• Fuzeon blocks HIV from entering healthy cells.
• It binds to the gp41 protein on the HIV virus.
• This prevents the virus from “fusing” with human cell membranes.
• By blocking entry, it stops the virus from multiplying inside cells.
• This helps lower the viral load and strengthens the immune system.

Fuzeon can cause side effects, with injection site reactions (ISRs) being the most common. These typically include:

• ISRs: Pain, redness, itching, swelling, hard lumps (induration), or bruising at the injection site. These reactions are often mild to moderate and usually go away over time. Rotating injection sites helps reduce them.
• Other common side effects: Diarrhea, nausea, fatigue, weight loss, sinus problems, stomach pain, cough, and flu-like symptoms.
• Pneumonia: In clinical trials, a higher rate of bacterial pneumonia was observed in patients taking Fuzeon, although a direct link has not been fully confirmed. Your doctor will monitor you for signs of pneumonia.
• Hypersensitivity reactions: Rarely, serious allergic reactions (rash, fever, chills, low blood pressure, liver problems) can occur. Seek immediate medical attention if these appear.
• Nerve pain: Very rarely, nerve pain or numbness can occur if injected too close to nerves.

Your healthcare team will monitor you closely for side effects.

Due to the nature of HIV treatment and Fuzeon’s specific properties, several warnings and precautions are important:

• Injection Site Reactions: These are very common. Proper injection technique and site rotation are crucial to minimize discomfort and prevent complications like cysts or abscesses.
• Hypersensitivity Reactions: While rare, severe allergic reactions can occur. Discontinue Fuzeon immediately and seek medical attention if signs of a systemic allergic reaction develop.
• Pneumonia: Be vigilant for symptoms of pneumonia (e.g., cough, fever, difficulty breathing) and report them to your doctor, especially if you have a weakened immune system.
• Immune Reconstitution Inflammatory Syndrome (IRIS): As your immune system gets stronger with HIV treatment, it might react to old, hidden infections (like tuberculosis or herpes), causing inflammatory symptoms.
• Not for HIV-2: Fuzeon is active only against HIV-1, not HIV-2.
• Pregnancy and Breastfeeding: Discuss with your doctor. HIV-infected women are generally advised not to breastfeed to avoid HIV transmission to the infant.
• Children: Safety and effectiveness are not established for children under 6 years of age.

Fuzeon has a relatively low risk of interacting with many other medicines compared to some other HIV drugs. This is because its active ingredient, enfuvirtide, is a peptide that is broken down in the body differently than most other medications, and it does not significantly affect the liver enzymes (CYP450) that process many drugs. Therefore, dose adjustments of other antiretroviral or non-antiretroviral drugs are generally not needed when taken with Fuzeon. However, it’s still extremely important to:

• Inform your doctor: Always tell your healthcare provider about ALL medications you are taking, including over-the-counter drugs, herbal supplements, and vitamins.
• Monitor other HIV drugs: Fuzeon is used in combination, so your doctor will manage the full regimen.
• Bleeding disorders: Patients with bleeding disorders (like hemophilia) or those on blood thinners may have an increased risk of bruising or bleeding at the injection site.

Your medical team will ensure that Fuzeon is safely integrated into your overall HIV treatment plan.

The standard dosage of Fuzeon for adults and adolescents (16 years and older) is 90 mg (1 mL) injected subcutaneously twice daily.

• Preparation: Each vial contains 108 mg of enfuvirtide powder, which is mixed with 1 mL of sterile water for injection to deliver a 90 mg dose.
• Pediatric Dosage: For children aged 6 to 16 years, the dosage is calculated based on body weight, typically 2 mg per kilogram (kg) twice daily, up to a maximum of 90 mg twice daily. The child’s weight should be monitored regularly, and the dose adjusted as they grow.
• Administration: Administered twice daily, usually in the morning and evening, by subcutaneous injection.
• Duration: Fuzeon is part of a lifelong HIV treatment regimen. You should continue taking it exactly as prescribed by your doctor, in combination with other antiretroviral medicines, as long as it remains effective and you can tolerate it.

Fuzeon is a prescription-only medication (POM). It is not available over-the-counter. Due to its specific use in treating HIV-1 infection, its injectable nature, and the need for its use in combination with other antiretroviral therapies, Fuzeon must be prescribed by a licensed physician, typically an infectious disease specialist or an HIV expert. The doctor will assess your viral load, treatment history, and any drug resistance to determine if Fuzeon is the appropriate addition to your HIV regimen. Ongoing medical supervision, including regular blood tests and monitoring for side effects, is essential throughout the course of treatment with Fuzeon.

• Fuzeon is a prescription-only medication (POM).
• Not available over-the-counter.
• Must be prescribed by a licensed physician, usually an HIV specialist.
• Its use requires careful assessment of HIV status and treatment history.
• Ongoing medical supervision and monitoring are essential.

What is Fuzeon? An antiretroviral drug used in HIV treatment.

2. What is the active ingredient? Enfuvirtide.

3. What class of drug is it? HIV fusion inhibitor.

4. How does it work? Blocks HIV from entering CD4 cells by binding to gp41 protein.

5. Is it prescription or OTC? Prescription only.

6. Is it a controlled substance? No.

7. Is a generic available? No, only brand Fuzeon is marketed.

8. What dosage forms exist? Lyophilized powder for subcutaneous injection.

9. How is it administered? Injected under the skin (subcutaneous).

10. What is the usual dose? 90 mg twice daily for adults.

11. What infections does it treat? HIV‑1 infection in combination with other antiretrovirals.

12. Is it used alone? No, always combined with other HIV medicines.

13. What are common side effects? Injection site reactions, rash, nausea, diarrhea, fatigue.

14. What are serious risks? Pneumonia, hypersensitivity reactions, immune reconstitution syndrome.

15. Can it be used in children? Yes, approved for children ≥6 years.

16. Can it be used in pregnancy? Only if benefits outweigh risks; consult a doctor.

17. How quickly does it work? Begins lowering viral load within weeks when combined therapy is effective.

18. Is monitoring required? Yes, viral load, CD4 count, and clinical status.

19. Where is it available? Specialty pharmacies and HIV treatment centers.

20. How should it be stored? Refrigerated; reconstituted solution used promptly.