Amprenavir

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  Structure of Amprenavir

• 3D model of Amprenavir

Amprenavir

Amprenavir is an antiretroviral drug used in the treatment of HIV/AIDS. It belongs to the class of drugs known as protease inhibitors, which work by inhibiting the action of the HIV-1 protease enzyme, thereby preventing the virus from maturing and replicating.

Mechanism of Action

Amprenavir works by binding to the active site of the HIV-1 protease enzyme. This enzyme is crucial for the cleavage of the viral polyprotein precursors into individual functional proteins necessary for the assembly of an infectious HIV virion. By inhibiting this enzyme, amprenavir prevents the maturation of the virus, thereby reducing the viral load in the body.

Pharmacokinetics

Amprenavir is administered orally and is absorbed in the gastrointestinal tract. It is metabolized primarily in the liver by the cytochrome P450 enzyme system, particularly CYP3A4. The drug has a relatively short half-life, necessitating multiple doses per day to maintain effective plasma concentrations.

Clinical Use

Amprenavir is used in combination with other antiretroviral agents for the treatment of HIV-1 infection. It is not recommended for use as monotherapy due to the rapid development of resistance. The drug is part of a Highly Active Antiretroviral Therapy (HAART) regimen, which is the standard of care for HIV treatment.

Side Effects

Common side effects of amprenavir include nausea, diarrhea, rash, and fatigue. More serious side effects can include liver toxicity and metabolic complications such as lipodystrophy and hyperlipidemia. Patients taking amprenavir should be monitored for these adverse effects.

Drug Interactions

Amprenavir is known to interact with a variety of other medications, primarily due to its metabolism by the cytochrome P450 system. It can affect the plasma concentrations of other drugs metabolized by CYP3A4, and vice versa. Caution is advised when co-administering amprenavir with other drugs that are substrates, inhibitors, or inducers of this enzyme.

Discontinuation

Amprenavir has largely been replaced by its prodrug, fosamprenavir, which has improved pharmacokinetic properties, allowing for reduced pill burden and dosing frequency. Fosamprenavir is converted to amprenavir in the body and provides similar therapeutic effects with a more convenient dosing regimen.

Related Pages

• HIV/AIDS
• Protease inhibitor (pharmacology)
• Highly Active Antiretroviral Therapy
• Fosamprenavir