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fosamprenavir (Rx)Brand and Other Names:Lexiva

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 700mg

oral suspension

  • 50mg/mL
more...

HIV Infection

Therapy-naive patients

  • 1400 mg PO q12hr (without ritonavir)
  • 1400 mg PO qDay (with ritonavir 100-200 mg qDay)
  • 700 mg PO q12hr (with ritonavir 100 mg q12hr)

Protease inhibitor-experienced patients

  • 700 mg PO q12hr (with ritonavir 100 mg q12hr)

Coadministration with efavirenz

  • 700 mg PO q12hr (with ritonavir 100 mg q12hr) plus 600 mg efavirenz qDay, or
  • 1400 mg PO qDay (with ritonavir 300 mg qDay) plus 600 mg efavirenz qDay

Combination with maraviroc

  • 700 mg PO q12hr (with ritonavir 100 mg q12hr) plus maraviroc 150 mg PO q12hr

Hepatic Impairment

Mild (Child-Pugh 5-6): 700 mg PO q12hr without ritonavir (therapy-naive); OR 700 mg q12hr with ritonavir 100 mg qDay (therapy-naive or protease inhibitor-experienced)

Moderate (Child-Pugh 7-9): 700 mg PO q12hr (therapy-naive) without ritonavir; OR 450 mg q12hr with ritonavir 100 mg qDay (therapy-naive or protease inhibitor-experienced)

Severe (Child-Pugh 10-15): 350 mg PO q12hr without ritonavir (therapy-naive); OR 300 mg q12hr with ritonavir 100 mg qD (therapy-naive or protease-inhibitor experienced)

Administration

Tablet: Take with meals if boosted with ritonavir; take without regard to meals if not boosted with ritonavir

Oral suspension: Adults should take without food

Dosage Forms & Strengths

tablet

  • 700mg

oral suspension

  • 50mg/mL
more...

HIV Infection (Protease Inhibitor Naive Patients)

<4 weeks: Safety and efficacy not established

Indicated for protease inhibitor-naive pediatric patients aged 4 weeks or older, and for protease inhibitor-experienced children aged 6 months or older

For infants, use only in those born at 38 weeks' gestation or greater and who have attained a postnatal age of 28 days

<11 kg: 45 mg/kg PO q12hr plus ritonavir 7 mg/kg q12hr  

11 to <15 kg: 30 mg/kg PO q12hr plus ritonavir 3 mg/kg q12hr

15 kg to <20 kg: 23 mg/kg PO q12hr plus ritonavir 3 mg/kg q12hr

≥20 kg: 18 mg/kg PO q12hr plus ritonavir 3 mg/kg q12hr

NOTE: When dosing with ritonavir, do not exceed adult dose of 700 mg/ritonavir 100 mg q12hr

Alternatively, protease inhibitor-naive children aged 2 yr or older may be administered 30 mg/kg PO q12hr (without ritonavir)

Unboosted Regimen

  • <2 years: Not recommended without ritonavir
  • >2 years and <47 kg: 30 mg/kg/dose PO q12hr; not to exceed 1400 mg PO q12hr
  • >2 years and ≥47 kg: 1400 mg PO q12hr

HIV Infection (Protease Inhibitor Experienced Patients)

<6 months

  • Not recommended

>6 months

  • <11 kg: 45 mg/kg/dose PO q12hr; not to exceed 700 mg fosamprenavir/100 mg ritonavir PO q12hr
  • 11-15 kg: 30 mg/kg/dose PO q12hr plus 3 mg/kg/dose ritonavir PO q12hr; not to exceed 700 mg fosamprenavir/100 mg ritonavir PO q12hr
  • 15 to <20 kg: 23 mg/kg/dose PO q12hr plus 3 mg/kg/dose ritonavir PO q12hr; not to exceed 700 mg fosamprenavir/100 mg ritonavir PO q12hr
  • ≥20 kg: 18 mg/kg/dose PO q12hr plus 3 mg/kg/dose ritonavir PO q12hr; not to exceed 700 mg fosamprenavir/100 mg ritonavir PO q12hr

Administration

Children should take oral suspension with food except:

≥47 kg: May use adult dosage with tabs (without ritonavir)

≥39 kg: May use adult dosage with tabs (with ritonavir) q12hr

Capsules can be used in patients weighing ≥33 kg

If vomiting occurs within 30 min, repeat dose

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Interactions

Interaction Checker

fosamprenavir and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            Nausea (30-50%)

            Rash (16-20%)

            Fatigue (11-15%)

            Diarrhea (5-13%)

            Increased triglycerides (11%)

            1-10%

            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%)

            <1%

            Stevens-Johnson syndrome

            Angioedema

            Myocardial infarction

            QT prolongation

            Nephrolithiasis

            Hypercholesterolemia

            Frequency Not Defined

            Spontaenous bleeding

            Acute hemolytic anemia

            Immune reconstitution syndrome

            Diabetes Mellitus

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            Warnings

            Contraindications

            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 w/ ritonavir another strong CYP3A4 inhibitor may have additive inhibitory effects; check Drug Interactions

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

            Cautions

            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

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            Pregnancy & Lactation

            Pregnancy Category: C

            Lactation: excreted in milk unknown; contraindicated

            Pregnancy Registry: to monitor maternal-fetal outcomes of pregnant women exposed to antiretroviral medications call 1-800-258-4263 or visit www.APRegistry.com

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

            more...
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            Pharmacology

            Mechanism of Action

            Prodrug converted to amprenavir (protease inhibitor) by cellular phosphatases in vivo; 700 mg fosamprenavir equivalent to 600 mg amprenavir

            Binds to active site of HIV-1 protease and thereby prevents processing of viral Gag and Gag-Pol polyprotein precursors, resulting in the formation of immature noninfectious viral particle

            Pharmacokinetics

            Half-Life: 7.7 hr

            Peak Plasma Time: 1.5-4 hr

            Protein Bound: 90%

            Absorption: 63%

            Metabolism: hepatic  CYP3A4

            Enzymes inhibited: CYP3A4

            Metabolite: Amprenavir

            Excretion: Feces (75%); urine (15%)

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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