Indinavir
Indications
Indinavir is used for:
HIV infection
Adult Dose
Oral
HIV infection
Adult: 800 mg PO q8hr
With ritonavir: 800 mg PO q12hr plus ritonavir 100-200 mg q12hr
Dosage Modifications
Concomitant CYP3A4 inhibitor: 600 mg PO q8hr
Concomitant administration with itraconazole, delavirdine, ketoconazole: 600 mg PO q8hr
Concomitant administration with efavirenz: 1000 mg PO q8hr
Concomitant administration with lopinavir and ritonavir: 600 mg PO q12hr
Concomitant administration with nelfinavir: 1200 mg PO q12hr
Concomitant administration with nevirapine: 1000 mg PO q8hr
Concomitant administration with rifabutin: Reduce rifabutin dose to half of standard dose plus increase indinavir to 1000 mg PO q8hr
Hepatic impairment: Mild-moderate (due to cirrhosis): 600 mg every 8 hr.
Child Dose
HIV-1 Infection
Neonates/infants: Safety and efficacy not established; should not be administered to neonates due to the risks associated with hyperbilirubinemia
4-15 years (investigational): 500 mg/m² PO q8hr
Renal Dose
Dose adjustment not studied
Administration
Take on empty stomach, with water, 1 hr prior or 2 hr after meal
May take with skim milk or low-fat meal
If taking with ritonavir, may take without regard to meals
Contra Indications
Hypersensitivity. Severe hepatic impairment.
Precautions
Proper hydration required (1.5 L liquids/day) to counter risk of nephrolithiasis/urolithiasis (much higher in children). Hyperbilirubinaemia may be exacerbated. Diabetes; haemophilia. Monitor for signs of lipodystrophy. Pregnancy and lactation.
Lactation: excretion in milk unknown; contraindicated
Pregnancy-Lactation
Pregnancy Category: C
Lactation: excretion in milk unknown; contraindicated
Interactions
Reduced absorption with antacids. Increased concentrations with ketoconazole, delavirdine, nelfinavir and ritonavir. Reduced efficacy with nevirapine, efavirenz or rifampicin. Increased risk of myopathy with statins. Increased concentrations of phosphodiesterase-5 inhibitors.
Potentially Fatal: Increased risk of cardiac arrhythmias with amiodarone, pimozide or cisapride. Increased sedation and respiratory depression with midazolam, alprazolam and triazolam. Increased risk of ergotism with ergot derivatives. Increased toxicity of drugs with narrow therapeutic index.
Side Effects
Side effects of Indinavir :
>10%
Nephrolithiasis/urolithiasis (29%, peds), Hyperbilirubinemia (14%), Nausea (12%), Pain (17%), Nephrolithiasis/urolithiasis (12%, adults)
1-10%
Abdominal pain (9%), Thrombocytopenia (1%), Back pain (8%), Dysuria (2%), Headache (6%), Fever (2%), Dizziness (3%), Diarrhea/vomiting (4-5%), Weakness (4%), Malaise (2%), Insomnia (3%), Fatigue (2%), Taste perversion (3%), Flank pain (3%), Pruritus (4%), Neutropenia (2%), Cough (2%)
<1%
Angina, Erythema multiforme, Hepatitis, Crystaluria, Angina
Mode of Action
Indinavir binds reversibly to HIV-protease which prevents cleavage of the viral precursor polyproteins. As a result, immature viral particles incapable of infecting other cells are formed.