AMPRENAVIR
| AMPRENAVIR (am-pre'na-vir) Agenerase Classifications: antiviral agent; antiretroviral agent; protease inhibitor; Therapeutic: antiretroviral; protease inhibitor Prototype: Saquinavir Pregnancy Category: C |
Availability
50 mg capsules; 15 mg/mL oral solution
Action
Amprenavir inhibits the activity of HIV-1 protease enzyme and thus prevents the cleavage of viral polyproteins essential for the maturation and proliferation of the HIV-1 virus. Amprenavir results in reduction of the viral load (HIV-RNA) in the plasma and an increase in the CD4 lymphocyte cell count.
Therapeutic Effect
The protease inhibitor activity results in the formation of immature, noninfectious viral particles. Effectiveness is measured by reduced viral particle count.
Uses
Treatment of HIV infection in combination with other antiretroviral agents.
Contraindications
Renal failure. Prior sensitivity to amprenavir; oral solution in children <4 y, infants, neonates; pregnancy (category C), lactation.
Cautious Use
History of hypersensitivity to other protease inhibitors (e.g., indinavir, ritonavir, saquinavir); hypersensitivity to sulfonamides; hepatic dysfunction; diabetes mellitus; diabetic ketoacidosis, hemophilia A and B; vitamin K deficiencies; anticoagulant therapy, oral contraceptives; coadministration with rifampin or sildenafil; antimicrobial resistance, hypercholesterolemia, hypertriglycerides, hyperglycemia, females, children, hepatic or renal impairment.
Route & Dosage
| HIV Infection Adult/Adolescent: PO 1200 mg capsules b.i.d. Child (4–12 y or <50 kg): PO 20 mg/kg b.i.d. capsules or 15 mg/kg t.i.d. capsules (max: 2400 mg/d); 22.5 mg/kg b.i.d. oral solution or 17 mg/kg t.i.d. oral solution Hepatic Impairment Child-Pugh score of 5–8: give 450 mg b.i.d.; Child-Pugh score 9–12: give 300 mg b.i.d. |
Administration
Oral- Give without regard to food, BUT not with high fat meal.
- Capsules & oral solution are not interchangeable on mg-for-mg basis.
- Give 1 h before/after antacid.
- Store tablets at 20°–25° C (68°–77° F). Do not refrigerate.
Adverse Effects (≥1%)
CNS: Oral/perioral paresthesia, peripheral paresthesia, depression, mood disorders. GI: Nausea, vomiting, diarrhea, taste disorders, increased triglycerides, hyperglycemia. Skin: Rash, Stevens-Johnson syndrome.Interactions
Drug: Administration with amiodarone, bepridil, dihydroergotamine, ergotamine, lidocaine, midazolam, quinidine, triazolam, and tricyclic antidepressants may cause life-threatening reactions; rifampin, rifabutin, oral contraceptives, phenobarbital, phenytoin, carbamazepine decrease amprenavir concentrations; amprenavir may increase dihydroergotamine, ergotamine sildenafil concentrations and toxicity; amprenavir may decrease methadone levels; monitor INR with warfarin; oral solution may cause antabuse reaction with disulfiram, metronidazole. Food: Decreased absorption with high-fat meal. Herbal: St. John's wort may decrease antiretroviral activity.Pharmacokinetics
Absorption: Oral solution is less absorbed than capsules. Peak: 1–2 h. Distribution: 90% bound to plasma proteins. Metabolism: In liver by CYP3A4. Elimination: 14% in urine, 75% in feces as metabolites. Half-Life: 7.1–10.6 h.Nursing Implications
Assessment & Drug Effects
- Monitor for therapeutic effectiveness which is indicated by elevated CD4 count & decreased HIV RNA copies.
- Monitor for & promptly notify physician of severe skin rash.
- Lab tests: Monitor blood glucose & HbA1c, Hgb & Hct, and lipid profile at periodic intervals.
- Note: Monitor blood levels for coadministered drugs including amiodarone, lidocaine, phenobarbital, phenytoin, quinidine, tricyclic antidepressants; monitor PT and INR with warfarin.
Patient & Family Education
- Follow directions for taking this drug (see ADMINISTRATION).
- Take drug exactly as prescribed at the indicated times. Missed dose: if less than 4 h, wait until the next scheduled dose; otherwise, take immediately.
- Do not take supplemental vitamin E with this drug unless approved by physician.
- Notify physician promptly about skin rash, nausea, vomiting, diarrhea, numbness or tingling around mouth or hands & feet.
- Inform physician of all other prescription/nonprescription drugs being taken. Serious interactions can occur.
- Use alternative barrier contraceptives rather than hormonal contraceptives while taking this drug.
- Note: Redistribution/accumulation of body fat may occur.
- Note: Diabetics may experience loss of glycemic control.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug