INDINAVIR SULFATE
(in-din'a-vir)
Crixivan
Classifications: antiinfective; antiviral agent; protease inhibitor
Prototype: Saquinavir
Pregnancy Category: C

Availability

100 mg, 200 mg, 333 mg, 400 mg capsules

Actions

Indinavir is an HIV protease inhibitor. HIV protease is an enzyme required to produce the polyprotein precursors of the functional proteins in infectious HIV.

Therapeutic Effects

Protease inhibitors prevent cleavage of the HIV viral polyproteins, resulting in formation of immature noninfectious virus particles. Indinavir binds to the protease active site and thus inhibits activity of the enzyme.

Uses

Treatment of HIV infection, usually in combination with other antiretroviral agents or protease inhibitors.

Contraindications

Hypersensitivity to indinavir; pregnancy (category C), lactation.

Cautious Use

Hepatic dysfunction, renal impairment, history of nephrolithiasis, history of adverse responses to other protease inhibitors. Safety and efficacy in children are not established.

Route & Dosage

HIV
Adult: PO 800 mg (2 x 400 mg) q8h 1 h before or 2 h after meal
With ritonavir: 800 mg b.i.d. plus 100–200 mg ritonavir b.i.d.

Administration

Oral

Adverse Effects (1%)

CNS: Fatigue, headache, insomnia, dizziness, somnolence, nervousness, agitation, anxiety, paresthesia, peripheral neuropathy, tremor, vertigo. CV: Palpitations. Hematologic: Anemia, splenomegaly, lymphadenopathy. GI: Nausea, diarrhea, abdominal discomfort, dyspepsia, stomatitis, anorexia, dry mouth, cholecystitis, cholestasis, constipation, flatulence. Skin: Body odor, rash, pruritus, seborrhea, skin ulceration, dry skin, sweating, urticaria. Other: Myalgia, allergic reaction, bronchitis, cough, rhinitis, taste alterations, visual disturbances, hyperglycemia, diabetes, kidney stones.

Interactions

Drug: Rifabutin, rifampin significantly decrease indinavir levels. Ketoconazole significantly increases indinavir levels. Indinavir could inhibit the metabolism and increase the toxicity of midazolam, sildenafil, tadalafil, trazodone, triazolam, vardenafil. Indinavir and didanosine should be administered at least 1 h apart on empty stomach to permit full absorption of each; increased ergotamine toxicity with indinavir. Herbal: St. John's wort, garlic decreases antiretroviral activity of indinavir.

Pharmacokinetics

Absorption: Rapidly absorbed from GI tract; a meal high in calories, fat, and protein significantly reduces absorption. Distribution: 60% protein bound. Metabolism: Metabolized in liver by cytochrome P4503A4 (CYP3A4). Elimination: Excreted primarily in feces (>80%), 20% excreted in urine.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug