Fosamprenavir Calcium

Generic Name: fosamprenavir calcium

Over-the-Counter (OTC)

Brand Names:

Fosamprenavir Calcium

11 DESCRIPTION Fosamprenavir calcium, USP is a prodrug of amprenavir, an inhibitor of HIV protease. The chemical name of fosamprenavir calcium, USP is (3S)-tetrahydrofuran-3-yl (1S,2R)-3-[[(4-aminophenyl) sulfonyl](isobutyl)amino]-1-benzyl-2-(phosphonooxy) propylcarbamate monocalcium salt. Fosamprenavir calcium, USP is a single stereoisomer with the (3S)(1S,2R) configuration. It has a molecular formula of C25H34CaN3O9PS and a molecular weight of 623.7.

Overview

11 DESCRIPTION Fosamprenavir calcium, USP is a prodrug of amprenavir, an inhibitor of HIV protease. The chemical name of fosamprenavir calcium, USP is (3S)-tetrahydrofuran-3-yl (1S,2R)-3-[[(4-aminophenyl) sulfonyl](isobutyl)amino]-1-benzyl-2-(phosphonooxy) propylcarbamate monocalcium salt. Fosamprenavir calcium, USP is a single stereoisomer with the (3S)(1S,2R) configuration. It has a molecular formula of C25H34CaN3O9PS and a molecular weight of 623.7.

Uses

1 INDICATIONS AND USAGE 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 calcium tablets plus ritonavir in protease inhibitor-experienced patients: The protease inhibitor-experienced patient trial was not large enough to reach a definitive conclusion that fosamprenavir calcium tablets plus ritonavir and lopinavir plus ritonavir are clinically equivalent [see Clinical Studies (14.2)] .

Dosage

2 DOSAGE AND ADMINISTRATION Therapy-Naive Adults: Fosamprenavir calcium tablets 1,400 mg twice daily; fosamprenavir calcium tablets 1,400 mg once daily plus ritonavir 200 mg once daily; fosamprenavir calcium tablets 1,400 mg once daily plus ritonavir 100 mg once daily; fosamprenavir calcium tablets 700 mg twice daily plus ritonavir 100 mg twice daily. (2.2) Protease Inhibitor-Experienced Adults: Fosamprenavir calcium tablets 700 mg twice daily plus ritonavir 100 mg twice daily.

Side Effects

6 ADVERSE REACTIONS Severe or life-threatening skin reactions have been reported with the use of fosamprenavir calcium [see Warnings and Precautions (5.2)]. The most common moderate to severe adverse reactions in clinical trials of fosamprenavir calcium were diarrhea, rash, nausea, vomiting, and headache. Treatment discontinuation due to adverse events occurred in 6.4% of subjects receiving fosamprenavir calcium and in 5.9% of subjects receiving comparator treatments. The most common adverse reactions leading to discontinuation of fosamprenavir calcium (incidence less than or equal to 1% of subjects) included diarrhea, nausea, vomiting, AST increased, ALT increased, and rash.

Interactions

7 DRUG INTERACTIONS Coadministration of fosamprenavir calcium with drugs that induce CYP3A4 may decrease amprenavir (active metabolite) concentrations leading to potential loss of virologic activity. (7, 12.3) Coadministration with drugs that inhibit CYP3A4 may increase amprenavir concentrations. (7, 12.3) Coadministration of fosamprenavir calcium or fosamprenavir calcium and ritonavir may result in clinically significant interactions with drugs metabolized by CYP3A4. (7) Coadministration of fosamprenavir calcium and ritonavir may result in clinically significant interactions with drugs metabolized by CYP2D6.

Warnings

5 WARNINGS AND PRECAUTIONS The concomitant use of fosamprenavir calcium 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 calcium should be discontinued for severe skin reactions, including Stevens-Johnson syndrome. (5.2) Fosamprenavir calcium 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. 4 CONTRAINDICATIONS Fosamprenavir calcium is 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.

Pregnancy

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to fosamprenavir calcium 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 calcium in pregnancy.

Storage

16 HOW SUPPLIED/STORAGE AND HANDLING Fosamprenavir calcium tablets, USP, 700 mg, are pink colored, coated, oval-shaped tablets with “RJ47” imprinted on one side with black ink and plain on the other side.

Frequently Asked Questions

What is Fosamprenavir Calcium used for?

1 INDICATIONS AND USAGE 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 calcium tablets plus ritonavir in protease inhibitor-experienced patients: The protease inhibitor-experienced patient trial was not large enough to reach a definitive conclusion that fosamprenavir calcium tablets plus ritonavir and lopinavir plus ritonavir are clinically equivalent [see Clinical Studies (14.2)] .

What are the side effects of Fosamprenavir Calcium?

6 ADVERSE REACTIONS Severe or life-threatening skin reactions have been reported with the use of fosamprenavir calcium [see Warnings and Precautions (5.2)]. The most common moderate to severe adverse reactions in clinical trials of fosamprenavir calcium were diarrhea, rash, nausea, vomiting, and headache. Treatment discontinuation due to adverse events occurred in 6.4% of subjects receiving fosamprenavir calcium and in 5.9% of subjects receiving comparator treatments. The most common adverse reactions leading to discontinuation of fosamprenavir calcium (incidence less than or equal to 1% of subjects) included diarrhea, nausea, vomiting, AST increased, ALT increased, and rash.

Can I take Fosamprenavir Calcium during pregnancy?

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to fosamprenavir calcium 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 calcium in pregnancy.

What are the important warnings for Fosamprenavir Calcium?

5 WARNINGS AND PRECAUTIONS The concomitant use of fosamprenavir calcium 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 calcium should be discontinued for severe skin reactions, including Stevens-Johnson syndrome. (5.2) Fosamprenavir calcium 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. 4 CONTRAINDICATIONS Fosamprenavir calcium is 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.

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Medical Disclaimer

This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.