Telzir

Telzir - General Information

Telzir is a prodrug of amprenavir, an inhibitor of human immunodeficiency virus (HIV) protease.

Pharmacology of Telzir

Telzir is a pro-drug of the protease inhibitor and antiretroviral drug amprenavir. The human body metabolizes fosamprenavir in order to form amprenavir, which is the active ingredient. That metabolization increases the duration that amprenavir is available, making fosamprenavir a slow-release version of amprenavir and thus reducing the number of pills required versus standard amprenavir.

Telzir for patients

Telzir Interactions

Telzir Contraindications

LEXIVA 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.
• when coadministered with drugs that are highly dependent on CYP3A4 for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events (Table 1).

Table 1. Drugs Contraindicated With LEXIVA

• when coadministered with ritonavir in patients receiving the antiarrhythmic agents flecainide and propafenone. If LEXIVA is coadministered with ritonavir, reference should be made to the full prescribing information for ritonavir for additional contraindications.

Additional information about Telzir

Telzir Indication: Indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus (HIV-1) infection.
Mechanism Of Action: Telzir is a prodrug that is rapidly hydrolyzed to amprenavir by cellular phosphatases in the gut epithelium as it is absorbed. Amprenavir is an inhibitor of HIV-1 protease. Amprenavir binds to the active site of HIV-1 protease and thereby prevents the processing of viral Gag and Gag-Pol polyprotein precursors, resulting in the formation of immature non-infectious viral particles.
Drug Interactions: Alprazolam Amprenavir increases the effect and toxicity of benzodiazepine
Clorazepate Amprenavir increases the effect and toxicity of benzodiazepine
Diazepam Amprenavir increases the effect and toxicity of benzodiazepine
Flurazepam Amprenavir increases the effect and toxicity of benzodiazepine
Midazolam Amprenavir increases the effect and toxicity of benzodiazepine
Triazolam Amprenavir increases the effect and toxicity of benzodiazepine
Warfarin The protease inhibitor increases the anticoagulant effect
Acenocoumarol The protease inhibitor increases the anticoagulant effect
Dicumarol The protease inhibitor increases the anticoagulant effect
Anisindione The protease inhibitor increases the anticoagulant effect
Aluminium The antiacid decreases the absorption of amprenavir
Bismuth The antiacid decreases the absorption of amprenavir
Calcium The antiacid decreases the absorption of amprenavir
Magnesium oxide The antiacid decreases the absorption of amprenavir
Magnesium The antiacid decreases the absorption of amprenavir
Amiodarone The protease inhibitor increases the effect and toxicity of amiodarone
Astemizole Increased risk of cardiotoxicity and arrhythmias
Terfenadine Increased risk of cardiotoxicity and arrhythmias
Atorvastatin Amprenavir can possibly increase the statin toxicity
Lovastatin Amprenavir can possibly increase the statin toxicity
Simvastatin Amprenavir can possibly increase the statin toxicity
Bepridil Amprenavir increases the effect and toxicity of bepridil
Cisapride Amprenavir increases the effect and toxicity of cisapride
Cyclosporine The protease inhibitor increases the effect of cyclosporine
Delavirdine Decreased levels of delavirdine with increased levels of amprenavir
Dihydroergotamine Amprenavir increases the effect and toxicity of ergot derivative
Ergotamine Amprenavir increases the effect and toxicity of ergot derivative
Fentanyl The protease inhibitor increases the effect and toxicity of fentanyl
Fusidic Acid The protease inhibitor increases the effect and toxicity of fusidic acid
Methadone The protease inhibitor decreases the effect of methadone
Pimozide Amprenavir increases the effect and toxicity of pimozide
Ranolazine Increased levels of ranolazine - risk of toxicity
Rifabutin Amprenavir increases the effect and toxicity of rifabutin
Rifampin In presence of rifampin anticipate decrease of amprenavir efficiency
Sildenafil The protease inhibitor increases the effect and toxicity of sildenafil
St. John's Wort St. John's Wort decreases the effect of indinavir
Tacrolimus The protease inhibitor increases the effect and toxicity of tacrolimus
Vardenafil The protease inhibitor increases the effect and toxicity of
Food Interactions: Avoid alcohol, especially with the oral solution since it contains propylene glycol which competes with alcohol for alcohol dehydrogenase metabolism.
Take with or without food, however avoid lipid-rich meals.
Vitamin E increases fosamprenavir bioavailability.
Generic Name: Fosamprenavir
Synonyms: Not Available
Drug Category: Anti-HIV Agents; HIV Protease Inhibitors; Prodrugs
Drug Type: Small Molecule; Approved

Other Brand Names containing Fosamprenavir: Lexiva; Telzir;
Absorption: The absolute oral bioavailability of amprenavir after administration of fosamprenavir in humans has not been established. After administration of a single 1,400 mg dose in the fasted state, fosamprenavir oral suspension (50 mg/mL) and fosamprenavir tablets (700 mg) provided similar amprenavir exposures (AUC), however, the C_max of amprenavir after administration of the suspension formulation was 14.5 % higher compared with the tablet.
Toxicity (Overdose): Not Available
Protein Binding: Very high (approximately 90%); primarily bound to alpha 1 -acid glycoprotein. Higher amounts of unbound amprenavir present as amprenavir serum concentrations increase.
Biotransformation: In the gut epithelium during absorption, fosamprenavir is rapidly and almost completely hydrolyzed to amprenavir and inorganic phosphate prior to reaching the systemic circulation. Amprenavir is metabolized in the liver by the cytochrome P450 3A4 (CYP3A4) enzyme system.
Half Life: The plasma elimination half-life of amprenavir (the active metabolite) is approximately 7.7 hours.
Dosage Forms of Telzir: Tablet Oral
Suspension Oral
Chemical IUPAC Name: [(3S)-oxolan-3-yl] N-[(2S,3R)-4-[(4-aminophenyl)sulfonyl-(2-methylpropyl)amino]-1-phenyl-3-phosphonooxybutan-2-yl]carbamate
Chemical Formula: C25H36N3O9PS
Fosamprenavir on Wikipedia: https://en.wikipedia.org/wiki/Fosamprenavir
Organisms Affected: Human Immunodeficiency Virus