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HIV fusion inhibitor

Enfuvirtide

Brand names: Fuzeon

Enfuvirtide is an injectable HIV-1 fusion inhibitor used in combination with other antiretrovirals for treatment-experienced patients with multidrug-resistant HIV-1 infection.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It binds to the gp41 subunit of the viral envelope and blocks the conformational change required for fusion of the virus with the host cell membrane, thereby preventing viral entry.

Prescribing in practice

  • Injection-site reactions are very common and almost universal, and can include nodules, erythema and induration; rotating sites helps but reactions are the main limitation to therapy.
  • It must be given by subcutaneous injection and is used only in combination with an optimised background regimen.
  • It has been associated with an increased rate of bacterial pneumonia, so respiratory symptoms should be assessed promptly.

Monitoring

Monitor HIV viral load and CD4 count, injection sites for reactions, and for signs of pneumonia or hypersensitivity.

Counselling the patient

  • Rotate injection sites and learn correct subcutaneous technique to reduce local reactions.
  • Report any breathing difficulty, fever or cough promptly.
  • Use exactly as part of your full antiretroviral combination.

Evidence & guidelines

Enfuvirtide's efficacy in treatment-experienced patients was established in the TORO trials of optimised background regimens.

Reference: BHIVA HIV guidelines; EACS; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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