Version July 2025
HIV-1 infection, treatment: SubQ: 90 mg twice daily.
No dosage adjustment necessary.
No dosage adjustment necessary (has not been studied).
Refer to adult dosing.
(For additional information see "Enfuvirtide: Pediatric drug information")
HIV-1 infection, treatment: Note: Gene mutation and antiretroviral (ARV) resistance patterns should be evaluated (refer to https://www.iasusa.org/ for more information) when necessary. Although FDA approved, contemporary use is uncommon secondary to availability of more preferable options. The role in therapy is typically reserved when other options are not available; it is not recommended as initial therapy in patients who are ARV naive (Ref).
Children weighing ≥11 kg and Adolescents:
Weight-directed dosing: SubQ: 2 mg/kg/dose twice daily; maximum dose: 90 mg/dose.
Fixed dosing (weight-band): SubQ:
11 to 15.5 kg: 27 mg twice daily.
15.6 to 20 kg: 36 mg twice daily.
20.1 to 24.5 kg: 45 mg twice daily.
24.6 to 29 kg: 54 mg twice daily.
29.1 to 33.5 kg: 63 mg twice daily.
33.6 to 38 kg: 72 mg twice daily.
38.1 to 42.5 kg: 81 mg twice daily.
≥42.6 kg: 90 mg twice daily.
Children weighing ≥11 kg and Adolescents: No dosage adjustment necessary.
Children weighing ≥11 kg and Adolescents: No dosage adjustment necessary.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Central nervous system: Fatigue (20%), insomnia (11%)
Gastrointestinal: Diarrhea (32%), nausea (23%)
Local: Injection site reaction (98%; may include cyst at injection site, erythema at injection site, induration at injection site, injection site ecchymosis, injection site nodule, injection site pruritus, pain at injection site), injection site infection (children: 11%, adults: 2%)
1% to 10%:
Dermatologic: Folliculitis (2%)
Endocrine & metabolic: Weight loss (7%)
Gastrointestinal: Abdominal pain (4%), decreased appetite (3%), pancreatitis (3%), anorexia (2%), xerostomia (2%)
Hematologic & oncologic: Eosinophilia (2% to 9%)
Hepatic: Increased serum transaminases (4%, grade 4: 1%)
Infection: Infection (4% to 6%), herpes simplex infection (4%)
Neuromuscular & skeletal: Increased creatine phosphokinase (3% to 7%), limb pain (3%), myalgia (3%)
Ophthalmic: Conjunctivitis (2%)
Respiratory: Sinusitis (6%), cough (4%), bacterial pneumonia (3%), flu-like symptoms (2%)
<1%, postmarketing, and/or case reports: Amyloidosis (cutaneous; at the injection site), angina pectoris, anxiety, constipation, depression, dysgeusia, glomerulonephritis, Guillain-Barré syndrome, hyperglycemia; hypersensitivity exacerbation (to abacavir), hypersensitivity reaction (symptoms may include fever, hypotension, increased serum transaminases, nausea, skin rash, vomiting); increased amylase, increased gamma-glutamyl transferase, insomnia, increased serum lipase, increased serum triglycerides, liver steatosis, lymphadenopathy, neutropenia, peripheral neuropathy, pulmonary disease, renal failure, renal insufficiency, renal tubular necrosis, respiratory distress, sepsis, sixth nerve palsy, suicidal tendencies, thrombocytopenia, toxic hepatitis, weakness
Hypersensitivity to enfuvirtide or any component of the formulation
Concerns related to adverse effects:
• Hypersensitivity reactions: May cause hypersensitivity reactions (symptoms may include rash, fever, nausea, vomiting, chills, rigors, hypotension, and/or elevated liver transaminases). Additionally, immune mediated reactions (eg, glomerulonephritis, Guillain-Barré syndrome, primary immune complex reaction, respiratory distress) have been reported. Discontinue therapy immediately if systemic reactions occur; do not rechallenge patient.
• Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves’ disease, polymyositis, Guillain-Barré syndrome) later in therapy; further evaluation and treatment may be required.
• Injection site reactions: Local injection site reactions are common. Administration using a needle-free device has been associated with nerve pain (including neuralgia and/or paresthesia lasting up to 6 months), bruising, and hematomas when administered at sites where large nerves are close to the skin; only administer medication in recommended sites.
• Pneumonia: Monitor closely for signs/symptoms of pneumonia; associated with an increased incidence during clinical trials, particularly in patients with a low CD4 cell count, high initial viral load, IV drug use, smoking, or a history of lung disease.
Disease-related concerns:
• Bleeding disorders: Use with caution in patients with coagulation disorders (eg, hemophilia) or receiving anticoagulants; increased risk of bleeding at injection site.
• Appropriate use: Use is not recommended in antiretroviral therapy-naive patients.
Genentech will discontinue all marketing and commercial distribution of Fuzeon in the United States on February 28, 2025. Further information is available at https://www.gene.com/media/statements/ps_081924.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution Reconstituted, Subcutaneous:
Fuzeon: 90 mg (1 ea)
No
Solution (reconstituted) (Fuzeon Subcutaneous)
90 mg (per each): $71.71
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Kit, Subcutaneous:
Fuzeon: 90 mg [DSC]
SubQ: Inject subcutaneously into upper arm, abdomen, or anterior thigh. Do not inject into moles, the navel, over a blood vessel or skin abnormalities such as scar tissue, surgical scars, bruises, tattoos, or burn sites. In addition, do not inject in or near sites where large nerves are close to the skin including the elbow, knee, groin, or buttocks. Rotate injection site, give injections at a site different from the preceding injection site; do not inject into any site where an injection site reaction is evident. Bioequivalence was found to be similar in a study comparing standard administration using a needle versus a needle-free device (Ref).
SubQ: Bring refrigerated reconstituted vials to room temperature before injection and visually inspect vial again; solution should be clear, colorless, and without particulate matter or bubbles.
Inject SubQ into upper arm, abdomen, or anterior thigh. Do not inject IM (severity of reactions is increased). Do not inject into skin abnormalities including directly over a blood vessel, into moles, bruises, scar tissue, near the navel, surgical scars, burn sites, or tattoos. Do not inject in or near sites where large nerves are close to the skin including near the elbow, knee, groin, and inferior or medial sections of the buttocks. Rotate injection site (ie, give injections at a site different from the preceding injection site); do not inject into any site where an injection site reaction is present. After injection, apply heat or ice to injection site or gently massage area to better disperse the dose, to minimize local injection reactions (Ref); discard unused portion of the vial (vial is for single use only).
HIV-1 infection, treatment: Treatment of HIV-1 infection in combination with other antiretroviral agents in treatment-experienced patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy.
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Atidarsagene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Atidarsagene Autotemcel. Risk X: Avoid
Betibeglogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Betibeglogene Autotemcel. Risk X: Avoid
Elivaldogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Elivaldogene Autotemcel. Management: Avoid use of antiretroviral medications for at least one month, or for the amount of time required for elimination of the retroviral medication, prior to stem cell mobilization and until the all apheresis cycles are finished Risk X: Avoid
Lovotibeglogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Lovotibeglogene Autotemcel. Risk X: Avoid
Orlistat: May decrease serum concentration of Antiretroviral Agents. Risk C: Monitor
Contraception is not required to initiate or continue antiretroviral therapy.
Enfuvirtide is not recommended (except in special circumstances) for patients with HIV who are not yet pregnant but are trying to conceive.
Maximum viral suppression sustained below the limits of detection prior to conception is recommended for all persons with HIV who are planning a pregnancy. Prior to pregnancy, select or make changes to a specific antiretroviral regimen as part of a shared decision-making process. In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth.
Health care providers caring for couples planning a pregnancy when one or both partners are diagnosed with HIV may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2024).
Enfuvirtide has minimal to low transfer across the human placenta.
Outcome data specific to enfuvirtide use in pregnancy are no longer being reviewed and updated in the Health and Humans Services (HHS) Perinatal Guidelines. Enfuvirtide is not recommended as initial therapy for pregnant patients with HIV; enfuvirtide is not recommended (except in special circumstances) in pregnant patients who have had antiretroviral therapy (ART) therapy in the past but are restarting, or who require a new ART regimen (due to poor tolerance or poor virologic response of current regimen). Patients who become pregnant while taking enfuvirtide may continue if viral suppression is effective and the regimen is well tolerated.
Maternal antiretroviral therapy (ART) may be associated with adverse pregnancy outcomes, including preterm birth, low birth weight, and small for gestational age infants. High viral loads are also associated with adverse outcomes, including preterm birth and pregnancy loss. Treatment improves the health of the pregnant patient and reduces the risk of perinatal transmission. Do not withhold appropriate maternal ART due to concerns for adverse neonatal outcomes. Closely monitor for pregnancy complications. Document in utero ART exposure in the long-term medical record of a child born without HIV; evaluate for potential metabolic dysfunction if significant organ system abnormalities of unknown etiology (particularly of the CNS or heart) develop.
ART is recommended for all pregnant people with HIV to maximize their health, maintain the viral load below the limit of an ultrasensitive assay detection, and reduce the risk of perinatal transmission. Start ART prior to conception or as soon as possible during pregnancy. During pregnancy, select or make changes to a specific antiretroviral regimen as part of a shared decision-making process. Patients on fully suppressive regimens prior to pregnancy generally may continue the same regimen considering known pregnancy outcomes and pharmacokinetic data. Monitor pregnant patients more frequently than nonpregnant patients. ART initiated during pregnancy can be modified after delivery. In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth.
Data collection to monitor pregnancy and infant outcomes following exposure to ART is ongoing. Enroll all patients exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263).
Health care providers caring for pregnant patients with HIV infection and their infants may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2024).
It is not known if enfuvirtide is present in breast milk.
Provide patient-centered evidence-based counseling for infant feeding options as early as possible in pregnancy.
• Using properly prepared formula or pasteurized banked donor milk eliminates the risk of postnatal HIV transmission via breastfeeding.
• Counsel patients on antiretroviral therapy (ART) who achieve and maintain a consistently undetectable plasma viral load during pregnancy and postnatally about feeding options, including breastfeeding, formula feeding, or banked donor milk. Maintaining maximum viral suppression decreases but does not eliminate the risk of HIV transmission via breast milk. Temporary discontinuation of breastfeeding and use of replacement feeding may be required if maternal viral load becomes detectable or if mastitis or bleeding nipples develop. Permanent discontinuation of breastfeeding is recommended if the maternal HIV RNA is ≥200 copies/mL.
• Formula feeding or banked donor milk is recommended for persons with HIV who are not on ART and/or do not have sustained viral suppression. Provide the infant presumptive antiretroviral therapy throughout breastfeeding and for up to 6 weeks after the last exposure to breast milk if the breastfeeding parent does not have sustained viral suppression but breastfeeding is continued; conduct infant virologic diagnostic testing at specified intervals.
• When the HIV status at delivery is not known, breast milk may be expressed and stored until a negative test is available.
• Discontinue breastfeeding immediately if HIV infection is diagnosed after breastfeeding has been initiated.
• Evaluate and provide support for maternal conditions that would make adherence to postpartum ART difficult.
Information is available for counseling and managing patients with HIV who are considering breastfeeding (1-888-448-8765). In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth (HHS [perinatal] 2024).
Viral load; CD4 count; hypersensitivity and injection site reactions; pediatric weight (periodically; adjust dose accordingly); signs and symptoms of pneumonia
Binds to the first heptad-repeat (HR1) in the gp41 subunit of the viral envelope glycoprotein. Inhibits the fusion of HIV-1 virus with CD4 cells by blocking the conformational change in gp41 required for membrane fusion and entry into CD4 cells
Absorption: SubQ: Absorption is comparable when injected into abdomen, arm, or thigh
Distribution: Vd: 5.5 ± 1.1 L ; CSF concentrations (2-18 hours after administration; n=4): nondetectable (<0.025 mcg/mL)
Protein binding: 92%; primarily to albumin, but also to alpha-1 acid glycoprotein (to a lesser extent)
Metabolism: Expected to undergo catabolism via peptidases and proteinases in the liver and kidneys to amino acids; amino acids would then be recycled in the body pool. A deaminated metabolite (with 20% activity compared to parent drug) was formed via hydrolysis during in vitro human microsomal and hepatocyte studies.
Bioavailability: SubQ: Absolute: 84.3% ± 15.5%; Note: Bioequivalence was found to be similar in a study comparing standard administration using a needle versus a needle-free device.
Half-life elimination: 3.8 ± 0.6 hours
Time to peak: SubQ: Single dose: Median: 8 hours (range: 3 to 12 hours); Multiple dosing: Median: 4 hours (range: 4 to 8 hours)
