Fosamprenavir

Fosamprenavir is an HIV-1 antiretroviral agent [see Microbiology (12.4) ] .

• Fosamprenavir calcium tablets are indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus (HIV-1) infection. The following points should be considered when initiating therapy with fosamprenavir plus ritonavir in protease inhibitor-experienced patients: • The protease inhibitor-experienced patient trial was not large enough to reach a definitive conclusion that fosamprenavir plus ritonavir and lopinavir plus ritonavir are clinically equivalent [see Clinical Studies (14.2) ] .ICD-10: B20

• • Fosamprenavir calcium tablets are contraindicated in patients with previously demonstrated clinically significant hypersensitivity (e.g., Stevens-Johnson syndrome) to any of the components of this product or to amprenavir. • Fosamprenavir calcium tablets are contraindicated when coadministered with drugs that are highly dependent on cytochrome P450 (CYP)3A4 for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events.contraindicated

• Therapy-Naive Adults: Fosamprenavir 1,400 mg twice daily; fosamprenavir 1,400 mg once daily plus ritonavir 200 mg once daily; fosamprenavir 1,400 mg once daily plus ritonavir 100 mg once daily; fosamprenavir 700 mg twice daily plus ritonavir 100 mg twice daily. ( 2.2 ) • Protease Inhibitor-Experienced Adults: Fosamprenavir 700 mg twice daily plus ritonavir 100 mg twice daily. ( 2.2 ) • Pregnant Patients: Fosamprenavir 700 mg twice daily plus ritonavir 100 mg twice daily should only be considered in women who are already on a stable twice-daily regimen of fosamprenavir/ritonavir 700 mg/100 mg prior to pregnancy and who are virologically suppressed (HIV-1 RNA less than 50 copies per mL). ( 2.2 ) • Pediatric Patients (aged at least 4 weeks to 18 years): Dosage should be calculated based on body weight (kg) and should not exceed adult dose. ( 2.3 ) • Hepatic Impairment: Recommended adjustments for patients with mild, moderate, or severe hepatic impairment. ( 2.4 ) Dosing Considerations • Fosamprenavir calcium tablets may be taken with or without food. ( 2.1 ) 2.1 General Dosing Information Fosamprenavir calcium tablets may be taken with or without food. Higher-than-approved dose combinations of fosamprenavir plus ritonavir are not recommended due to an increased risk of transaminase elevations [see Overdosage (10) ] . When fosamprenavir is used in combination with ritonavir, prescribers should consult the full prescribing information for ritonavir. 2.2 Adults Therapy-Naive Adults • Fosamprenavir 1,400 mg twice daily (without ritonavir).

• The concomitant use of fosamprenavir with ritonavir and certain other drugs may result in known or potentially significant drug interactions. Consult the full prescribing information prior to and during treatment for potential drug interactions. ( 5.1 , 7.3 ) • Fosamprenavir should be discontinued for severe skin reactions, including Stevens-Johnson syndrome. ( 5.2 ) • Fosamprenavir should be used with caution in patients with a known sulfonamide allergy. ( 5.3 ) • Use of higher-than-approved doses may lead to transaminase elevations. Patients with hepatitis B or C are at increased risk of transaminase elevations. ( 5.4 ) • Patients receiving fosamprenavir may develop new onset or exacerbations of diabetes mellitus, hyperglycemia ( 5.5 ), immune reconstitution syndrome ( 5.6 ), increase of body fat ( 5.7 ), and elevated triglyceride and cholesterol concentrations ( 5.8 ). Monitor cholesterol and triglycerides prior to therapy and periodically thereafter. • Acute hemolytic anemia has been reported with amprenavir. ( 5.9 ) • Hemophilia: Spontaneous bleeding may occur, and additional factor VIII may be required. ( 5.10 ) • Nephrolithiasis: Cases of nephrolithiasis have been reported with fosamprenavir. ( 5.11 ) 5.1 Risk of Serious Adverse Reactions Due to Drug Interactions Initiation of fosamprenavir/ritonavir, a CYP3A inhibitor, in patients receiving medications metabolized by CYP3A, or initiation of medications metabolized by CYP3A in patients already receiving fosamprenavir/ritonavir may increase plasma concentrations of medications metabolized by CYP3A.

• Severe or life-threatening skin reactions have been reported with the use of fosamprenavir [see Warnings and Precautions (5.2) ] . • The most common moderate to severe adverse reactions in clinical trials of fosamprenavir were diarrhea, rash, nausea, vomiting, and headache. • Treatment discontinuation due to adverse events occurred in 6.4% of subjects receiving fosamprenavir and in 5.9% of subjects receiving comparator treatments. The most common adverse reactions leading to discontinuation of fosamprenavir (incidence less than or equal to 1% of subjects) included diarrhea, nausea, vomiting, AST increased, ALT increased, and rash. • In adults the most common adverse reactions (incidence greater than or equal to 4%) are diarrhea, rash, nausea, vomiting, and headache. ( 6.1 ) • Vomiting and neutropenia were more frequent in pediatrics than in adults. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Lactation: Breastfeeding is not recommended due to potential for HIV transmission. ( 8.2 ) 8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to fosamprenavir during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary Limited data are available for use of fosamprenavir in pregnancy. Fosamprenavir 700 mg twice daily taken with ritonavir 100 mg twice daily should only be considered in pregnant patients who are already on a stable twice-daily regimen of fosamprenavir/ritonavir 700 mg/100 mg prior to pregnancy, and who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) (see Clinical Considerations and Data ). There are insufficient human data on the use of fosamprenavir during pregnancy to adequately assess a drug-associated risk for birth defects and miscarriage. Given the limited number of pregnancies exposed to fosamprenavir-based regimens, no conclusions can be drawn on the safety of fosamprenavir in pregnancy. The background risk for major birth defects and miscarriage for the indicated population is unknown. The background rate for major birth defects in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP) is 2.7% (see Data ) .

Metabolism

The pharmacokinetic properties of amprenavir after administration of fosamprenavir, with or without ritonavir, have been evaluated in both healthy adult volunteers and in HIV-1–infected subjects; no substantial differences in steady-state amprenavir concentrations were observed between the 2 populations. The pharmacokinetic parameters of amprenavir after administration of fosamprenavir (with and without concomitant ritonavir) are shown in Table 7.

In a healthy volunteer repeat-dose pharmacokinetic trial evaluating high-dose combinations of fosamprenavir plus ritonavir, an increased frequency of Grade 2/3 ALT elevations (greater than 2.5 x ULN) was observed with fosamprenavir 1,400 mg twice daily plus ritonavir 200 mg twice daily (4 of 25 subjects). Concurrent Grade 1/2 elevations in AST (greater than 1.25 x ULN) were noted in 3 of these 4 subjects. These transaminase elevations resolved following discontinuation of dosing. There is no known antidote for fosamprenavir. It is not known whether amprenavir can be removed by peritoneal dialysis or hemodialysis, although it is unlikely as amprenavir is highly protein bound. If overdosage occurs, the patient should be monitored for evidence of toxicity and standard supportive treatment applied as necessary.

• Apr 15, 2016ANDAANDA204060Mylan
• Nov 20, 2019ANDAANDA204024Sun Pharm

1. 1Drug Interaction3728%
2. 2Anaemia2721%
3. 3Alanine Aminotransferase Increased2620%
4. 4Aspartate Aminotransferase Increased2620%
5. 5Haematuria2620%
6. 6Vomiting2620%
7. 7Acute Kidney Injury2519%
8. 8Blood Bilirubin Increased2519%
9. 9Cerebral Ischaemia2519%
10. 10Cystitis Noninfective2519%
11. 11Febrile Neutropenia2519%
12. 12Infection2519%
13. 13Myalgia2519%
14. 14Pulmonary Embolism2519%
15. 15Thrombosis2519%

The 10 most recently updated of 67 ClinicalTrials.gov registrations naming Fosamprenavir as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Fosamprenavir for Laryngopharyngeal Upper Airway Tissue Treatment and Enzyme Reduction
  Not yet recruiting · Phase 2 · Interventional · 104 enrolled · Medical College of Wisconsin
  NCT04383262updated 2026-05-01
• Dual Boosted Protease Inhibitor Regimens Without Any Additional Antiretroviral Therapy in HIV-1 Infected Patients (ANRS127)
  Completed · Phase 2 · Interventional · 61 enrolled · French National Agency for Research on AIDS and Viral Hepatitis
  NCT00122603updated 2026-04-02
• Trial to Evaluate the Interest of a Reductive Anti Retroviral Strategy Using Dual Therapy Inspite of Triple Therapy
  Completed · Phase 3 · Interventional · 224 enrolled · University Hospital, Tours
  NCT02302547updated 2025-12-26
• Pharmacokinetic Study of Antiretroviral Drugs and Related Drugs During and After Pregnancy
  Completed · Observational · 1,578 enrolled · National Institute of Allergy and Infectious Diseases (NIAID)
  NCT00042289updated 2025-12-02
• Study to Compare Bictegravir/Lenacapavir Versus Current Therapy in People With HIV-1 Who Are Successfully Treated With a Complicated Regimen
  Active not recruiting · Phase 2 · Phase 3 · Interventional · 689 enrolled · Gilead Sciences
  NCT05502341updated 2025-10-14
• Oral Fosamprenavir + Sodium Alginate for GERD
  Not yet recruiting · Phase 2 · Interventional · 60 enrolled · Medical College of Wisconsin
  NCT06704100updated 2025-10-06
• Study Of An Investigational Regimen Including FDA Approved HIV Drugs In HIV-Infected Pediatric Subjects
  Completed · Phase 2 · Interventional · 59 enrolled · ViiV Healthcare
  NCT00071760updated 2023-10-10
• Using Drug Levels and Drug Resistance Testing to Select Effective Anti-HIV Drug Combinations in Patients With Drug-resistant HIV
  Completed · Phase 2 · Interventional · 53 enrolled · National Institute of Allergy and Infectious Diseases (NIAID)
  NCT00027339updated 2021-11-01
• Dual Versus Triple Protease Inhibitor Combinations, Including Ritonavir, in HIV Infected People
  Completed · Interventional · 56 enrolled · National Institute of Allergy and Infectious Diseases (NIAID)
  NCT00028366updated 2021-11-01
• IMPAACT P1080: Psychiatric and Antiretroviral Medication Concentrations in HIV-infected and Uninfected Children and Adolescents
  Completed · Observational · 127 enrolled · International Maternal Pediatric Adolescent AIDS Clinical Trials Group
  NCT01232361updated 2021-08-03

Frequently asked questions

How does Fosamprenavir work?

Fosamprenavir is an HIV-1 antiretroviral agent [see Microbiology (12.4) ] .

What is Fosamprenavir used for?

According to FDA labeling, Fosamprenavir carries indications including: Fosamprenavir calcium tablets are indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus (HIV-1) infection. The following points should be considered when initiating therapy with fosamprenavir plus ritonavir in protease inhibitor-experienced patients: • The protease inhibitor-experienced patient trial was not large enough to reach a definitive conclusion that fosamprenavir plus ritonavir and lopinavir plus ritonavir are clinically equivalent [see Clinical Studies (14.2) ] .. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Fosamprenavir?

Fosamprenavir is classified as Protease inhibitors, HIV Protease Inhibitors, Decreased Protein Synthesis, Increased Immunologically Active Molecule Activity.

What are the brand names for Fosamprenavir?

Fosamprenavir is marketed under brand names including Lexiva.

What are the contraindications for Fosamprenavir?

Fosamprenavir labeling lists contraindications including: • Fosamprenavir calcium tablets are contraindicated in patients with previously demonstrated clinically significant hypersensitivity (e.g., Stevens-Johnson syndrome) to any of the components of this product or to amprenavir. • Fosamprenavir calcium tablets are contraindicated when coadministered with drugs that are highly dependent on cytochrome P450 (CYP)3A4 for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events.. Always consult the full prescribing information and a clinician.