Amprenavir is an antiretroviral protease inhibitor used in the therapy and prevention of human immunodeficiency virus (HIV) infection and the acquired immunodeficiency syndrome (AIDS). Fosamprenavir is a prodrug of amprenavir that has better oral bioavailability and that has largely replaced amprenavir in clinical use.
Both amprenavir and fosamprenavir can cause transient and usually asymptomatic elevations in serum aminotransferase levels and are rare causes of clinically apparent, acute liver injury. In coinfected patients, hepatic injury during highly active antiretroviral therapy may be a result of exacerbation of the underlying chronic hepatitis B or C rather than a direct toxic effect of the medication.
Amprenavir (am pren' a vir) is sulfonamide nonpeptide HIV protease inhibitor that acts by binding to the catalytic site of the viral protease, thereby preventing the cleavage of HIV polyprotein precursors into mature, functional proteins that are necessary for viral replication. Fosamprenavir (fos" am pren' a vir) is a phosphonooxy prodrug of amprenavir which is more water soluble and has greater bioavailability than amprenavir. Fosamprenavir is rapidly converted to amprenavir in the intestinal mucosa.
Fosamprenavir was approved for use in the United States in 1999 and fosamprenavir in 2003 for the therapy of HIV infection in adults and children in combination with other antiretroviral agents. Amprenavir was previously available in capsules of 50 mg under the brand name Agenerase. The pill burden of amprenavir therapy made fosamprenavir preferable and amprenavir is no longer availble in the United States.
Fosamprenavir is available in tablets of 700 mg and in a liquid solution for pediatric use (50 mg/mL) under the brand name Lexiva. Both agents are typically used in combination with low "booster" doses of ritonavir (100 or 200 mg daily). The recommended dose of fosamprenavir is 1400 mg twice daily when given without ritonavir or 1400 mg once daily when given with ritonavir. The dose in children is weight based.
Drugs for HIV Infection, in the Subclass Antiretroviral Agents
- Nonnucleoside Reverse Transcriptase Inhibitors (HIV)
- Nucleoside Analogues (HIV)
- Protease Inhibitors (HIV)
HCV NS5A Inhibitors
HCV NS5B (Polymerase) Inhibitors
- Asunaprevir, Boceprevir, Glecaprevir, Grazoprevir, Paritaprevir, Simeprevir, Telaprevir, Voxilaprevir
Drugs for Herpes Virus Infections (HSV, CMV, others)
Drugs for Influenza