Enfuvirtide

Pronunciation: en-FYOO-veer-tide
Class: Fusion inhibitor

Trade Names

Fuzeon
- Injection 90 mg/mL

Pharmacology

Interferes with entry of HIV-1 into cells by inhibiting fusion of viral and cellular membranes.

Slideshow: Flashback: FDA Drug Approvals 2013

Pharmacokinetics

Absorption

Following a 90 mg subcutaneous injection, the mean C max was 4.59 mcg/mL, AUC was 55.8 mcg•h/mL, and median t max was 8 h. The absolute bioavailability was 84.3%.

Distribution

After IV administration, the mean Vd was 5.5 L. Enfuvirtide is approximately 92% protein bound.

Metabolism

Enfuvirtide is expected to undergo catabolism to its constituent amino acids, with subsequent recycling into the body pool.

Elimination

The elimination t ½ is 3.8 h and the mean apparent clearance is 24.8 mL/h/kg.

Special Populations

Gender

Clearance is 20% lower in women than men; however, no dose adjustment is recommended for gender.

Indications and Usage

In combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy.

Contraindications

Standard considerations.

Dosage and Administration

Adults

subcutaneous 90 mg twice daily.

Children 6 yr of age and older

subcutaneous 2 mg/kg twice daily (max, 90 mg twice daily).

General Advice

  • For subcutaneous administration only. Not for intradermal, IM, or IV administration.
  • Inject prescribed dose into upper arm, anterior thigh, or abdomen.
  • Administer each injection at a site different from the preceding injection site and only where there is no current injection site reaction from an earlier dose.
  • Do not inject into moles, scar tissue, bruises, or the navel.
  • Follow manufacturer's instructions for reconstitution and administration. Use Sterile Water for Injection for reconstitution.
  • Do not administer if particulate matter, bubbles, cloudiness, or discoloration noted.
  • Do not mix other medications in same syringe.
  • Reconstituted solution should be injected immediately or kept refrigerated in original vial for up to 24 h. Refrigerated solution should be allowed to come to room temperature before injection and inspected visually again to ensure that the contents are fully dissolved in solution and that the solution is clear, colorless, and without bubbles or particulate matter.

Storage/Stability

  • Discard any unused solution. Do not save unused solution for later administration.
  • Store unopened vials at controlled room temperature (59° to 86°F). Reconstituted solution should be stored under refrigeration (36° to 46°F) and used within 24 h.

Drug Interactions

None well documented.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Fatigue; peripheral neuropathy; taste disturbances; insomnia; depression; anxiety; decreased appetite; Guillain-Barre syndrome; sixth nerve palsy.

Dermatologic

Injection site reactions (including erythema, induration, nodules or cysts, abscess, cellulitis, pain, discomfort, pruritus, ecchymosis); skin papilloma.

EENT

Conjunctivitis.

GI

Diarrhea; nausea; anorexia; constipation; upper abdominal pain; pancreatitis.

Genitourinary

Renal insufficiency (glomerulonephritis); renal failure.

Hematologic

Lymphadenopathy; thrombocytopenia; neutropenia.

Metabolic

Weight decrease; hyperglycemia.

Respiratory

Cough; sinusitis; pneumonia.

Miscellaneous

Herpes simplex; influenza; flu-like symptoms; myalgia; fever.

Precautions

Pregnancy

Category B .

Lactation

Undetermined; however, HIV-infected mothers should not breast-feed their infants.

Children

Safety and efficacy not established in children less than 6 yr of age.

Hypersensitivity

May occur and recur on rechallenge.

Pneumonia

An increased incidence of bacterial pneumonia observed.

Patient Information

  • If patient or caregiver will be administering at home, review patient information leaflet and “Injection Instructions” with the patient or caregiver. Ensure that the patient or caregiver understands how to store, prepare, and administer the dose, and dispose of used equipment and supplies. The first injection should be performed under the supervision of a qualified health professional.
  • Instruct patient or caregiver to administer prescribed dose twice daily.
  • Advise patient that if a dose is missed to take it as soon as remembered. However, if it is close to the time for the next scheduled dose, wait and take the next dose as scheduled. Caution patient not to administer 2 doses at the same time.
  • Warn patient that this drug is not to be used by itself but is combined with other antiretroviral agents.
  • Advise patient not to change the dose or dosing schedule of this medication or any other antiretroviral medication unless advised by health care provider.
  • Advise patient that injection site reactions are common and analgesics (eg, acetaminophen, ibuprofen) may be used to manage pain but to notify health care provider if multiple injection site reactions develop or if reactions are intolerable.
  • Instruct patient to report the following symptoms immediately to health care provider: allergic reaction, fever, chills, persistent nausea or vomiting, signs of pneumonia (cough with fever, unexplained rapid breathing or shortness of breath), or signs of infection at injection site (eg, oozing, swelling, redness, pain, increasing heat).
  • Inform patient that drug does not completely eliminate HIV virus and, therefore, does not reduce risk of transmitting HIV. Appropriate precautions must still be followed.
  • Advise patient that drug is not a cure for HIV infection and that patient may continue to acquire illnesses associated with HIV infection, including opportunistic infections and to remain under a health care provider's care.
  • Advise patient that drug may cause dizziness and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.

Copyright © 2009 Wolters Kluwer Health.

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