Skip to content

Fosamprenavir

    Brands

    DEA Class; Rx

    Common Brand Names; Lexiva

    • HIV, Protease Inhibitors

    Protease inhibitor (PI)
    For the treatment of human immunodeficiency virus (HIV) infection in combination with other antiretroviral agents
    Prodrug of amprenavir; improved solubility compared to amprenavir allows for reduced pill burden

    Indicated for the treatment of human immunodeficiency virus (HIV) infection in combination with other antiretroviral agents.

    Hypersensitivity (eg, Stevens-Johnson syndrome) to fosamprenavir, amprenavir, or other component

    Concomitant use of drugs that depend heavily on CYP3A4 for clearance; metabolite amprenavir is a strong CYP3A4 inhibitor; use with ritonavir another strong CYP3A4 inhibitor may have additive inhibitory effects; check Drug Interactions

    Drugs that are contraindicated with fosamprenavir (with or without ritonavir) include lipid modifying agents (eg, lomitapide, lovastatin, simvastatin), alpha1-adrenoreptor agonists (eg, alfuzosin), antiarrhythmics (flecainide, propafenone), rifampin, ergot derivatives (dihydroergotamine, ergonovine, ergotamine, methylergonovine), cisapride, St. John’s wort, lurasidone, pimozide, sildenafil (when used for PAH), midazolam, and triazolam

    • Nausea (30-50%)
    • Rash (16-20%)
    • Fatigue (11-15%)
    • Diarrhea (5-13%)
    • Increased triglycerides (11%)
    • Increased serum lipase, ALT, AST (5-10%) in pts. treatment with concomitant ritonavir
    • Vomiting (2-6%)
    • Headache (2-4%)
    • Pruritus (7-8%)
    • Nausea (3-7%)
    • Abdominal pain (≤ 2%)
    • Increased hepatic transaminases (4-8%)

    New onset DM, exacerbation of pre-existing DM & hyperglycemia reported with unknown frequency/unknown causal relationship

    Sulfonamide allergy

    Monitor labs prior to and during treatment with Hepatitis B or C, or elevated transaminases

    Few reports of spontaneous bleeding in patients. with Hemophilia A and B

    During initial treatment, inflammatory response to indolent or residual opportunistic infections may occur and require treatment

    Fat redistribution with “cushingoid appearance” and “buffalo hump” may occur

    Increased risk for myocardial infarction (thought to be caused by protease inhibitors increasing risk of hyperlipidemia)

    Monitor triglycerides and cholesterol levels before initiating, then periodically; initiate clinical management of lipid disorders as required

    Combination treatment with ritonavir may lead to increased triglyceride level

    Unknown effect on activity of subsequently administered protease inhibitors

    Risk of immune reconstitution syndrome if used in combination with other antiretroviral drugs; autoimmune disorders (eg Graves disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of treatment

    Vomiting more common in children

    Cases of nephrolithiasis reported with fosamprenavir

    Acute hemolytic anemia reported with amprenavir

    Discontinue therapy if severe skin reactions including Stevens-Johnson syndrome occur

    There are insufficient prospective pregnancy data from Antiretroviral Pregnancy Registry (APR) to adequately assess risk of adverse developmental outcomes

    There is no information available on presence of amprenavir in human milk, the effects of the drug on breastfed infant, or effects of drug on milk production

    Adults

    2,800 mg/day PO.

    Geriatric

    2,800 mg/day PO.

    Adolescents

    20 kg or more: 36 mg/kg/day (Max: 1,400 mg) PO with ritonavir; 60 mg/kg/day (Max: 2,800 mg) PO without ritonavir (not recommended by HIV guidelines).

    Children

    2 years or older and at least 20 kg: 36 mg/kg/day (Max: 1,400 mg) PO with ritonavir; 60 mg/kg/day (Max: 1,400 mg) PO without ritonavir (not recommended by HIV guidelines).
    2 years or older and 15 kg to 19 kg: 46 mg/kg/day PO with ritonavir; 60 mg/kg/day PO without ritonavir (not recommended by HIV guidelines).
    2 years or older and 11 kg to 14 kg: 60 mg/kg/day PO with ritonavir; 60 mg/kg/day PO without ritonavir (not recommended by HIV guidelines).
    2 years or older and 10 kg: 90 mg/kg/day PO with ritonavir; 60 mg/kg/day PO without ritonavir (not recommended by HIV guidelines).
    younger than 2 years and 15 kg to 19 kg: 46 mg/kg/day PO with ritonavir.
    younger than 2 years and 11 kg to 14 kg: 60 mg/kg/day PO with ritonavir.
    younger than 2 years and less than 11 kg: 90 mg/kg/day PO with ritonavir.

    Infants

    15 kg to 19 kg: 46 mg/kg/day PO with ritonavir. HIV guidelines do not recommend use in infants under 6 months of age.
    11 kg to 14 kg: 60 mg/kg/day PO with ritonavir. HIV guidelines do not recommend use in infants under 6 months of age.
    less than 11 kg: 90 mg/kg/day PO with ritonavir. HIV guidelines do not recommend use in infants under 6 months of age.

    Neonates

    Safety and efficacy have not been established.

    Fosamprenavir

    tablet

    • 700mg

    oral suspension

    • 50mg/mL