Indinavir Sulfate

A to Z Drug Facts

  Action Inhibits human immunodeficiency virus (HIV) protease, the enzyme that cleaves viral polyprotein precursors into functional proteins in HIV-infected cells. Inhibition of this enzyme by indinavir results in formation of immature noninfectious viral particles.

  Indications Treatment of HIV infection in adults when antiretroviral therapy is warranted.

  Contraindications Concomitant therapy with amiodarone, cisapride, ergot derivatives, midazolam, pimozide, or trazolam; hypersensitivity to any component of product.

  Route/Dosage

ADULTS: PO 800 mg (two 400 mg capsules) q 8 hr.

  Interactions

Cisapride, Midazolam, Triazolam: Concomitant use is contraindicated.

Delavirdine: Serum levels of indinavir may be increased; consider a dose reduction of indinavir to 600 mg q 8 hr when administering delavirdine 400 mg bid.

Didanosine: Separate administration by at least 1 hr. The buffers in didanosine preparations may interfere with indinavir’s absorption.

Efavirenz: Serum levels of indinavir may be decreased; consider a dose increase of indinavir to 1000 mg q 8 hr.

Fentanyl: Indinavir may elevate plasma levels and prolong the half-life of fentanyl, increasing the risk of side effects.

Itraconazole: Serum levels of indinavir may be increased; consider a dose reduction of indinavir to 600 mg q 8 hr when administering ketoconazole.

Interleukins, Ritonavir, Sildenafil: Serum indinavir concentrations may be increased. Consider decreasing indinavir’s dose.

Rifabutin: Serum concentrations of rifabutin may be increased. A 50% reduction in rifabutin dosage is recommended by the manufacturer.

Rifampin: May induce enzymes that metabolize indinavir; concomitant use not recommended.

Sildenafil: Ritonavir may elevate sildenafil plasma levels, increasing the risk of adverse effects, including hypotension and visual changes.

St. John’s Wort: Serum levels of indinavir may be decreased, reducing the clinical effect.

  Lab Test Interferences None well documented.

  Adverse Reactions

CARDIOVASCULAR: Palpitation; syncope. CNS: Headache; insomnia; dizziness; somnolence; anxiety. DERMATOLOGIC: Rash; dry skin; pruritus. EENT: Pharyngitis; altered taste; blurred vision. GI: Nausea; vomiting; diarrhea; anorexia; acid reflux; dry mouth; abdominal pain; altered taste. GU: Nephrolithiasis; dysuria; hematuria. HEPATIC: Asymptomatic hyperbilirubinemia. OTHER: Asthenia; fatigue; flank pain; back pain; chest pain; malaise; fever; flu-like symptoms.

  Precautions

Pregnancy: Category C. Lactation: Undetermined. Children: Safety and efficacy not established. Hepatic Insufficiency/Cirrhosis: Lower indinavir doses may be required since indinavir is hepatically metabolized.

  Administration/Storage

• Administer drug without food but with water 1 hr before or 2 hr after a meal; alternatively, administer with other liquids (eg, skim milk, juice, coffee, tea) or a light meal (eg, dry toast with jelly, corn flakes with skim milk).
• The patient should drink 1.5 L (48 oz) of liquids in 24 hr.
• Store in a tightly closed container at room temperature, protected from moisture.

  Assessment/Interventions

• Obtain patient history.
• Assess for evidence of hepatic insufficiency prior to starting therapy.
• Assess for nephrolithiasis during therapy.

  Patient/Family Education

• Advise patient not to modify or discontinue treatment without first consulting the health care provider.
• Advise patient that this medicine must be taken at 8-hr intervals.
• If a dose is missed, the next dose should be taken as soon as possible but not doubled.
• If patient cannot take the drug with only water, the drug may be taken with other liquids or a light meal.
• Have patients store the drug in the original container to prevent moisture from affecting the drug.
• Advise patient that capsules should be used and stored in their original container.
• Inform patient that capsules are sensitive to moisture and the desiccant should remain in the bottle.
• Advise the patient that indinavir is not a cure for HIV, and that its long-term effects are unknown.
• Advise patient to contact health care provider if any of the following occurs: back/flank pain; pink or red-colored urine; yellowing of skin or eyes.

Books@Ovid
Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts