Indinavir is a protease inhibitor antiretroviral medication indicated for the treatment of human immunodeficiency virus (HIV-1) infection. It functions by selectively binding to the active site of the HIV-1 protease enzyme, thereby inhibiting the cleavage of viral polyprotein precursors into functional proteins required for viral replication. This action results in the production of immature, non-infectious viral particles, effectively reducing viral load and slowing disease progression. It is typically administered in combination with other antiretroviral agents as part of a highly active antiretroviral therapy (HAART) regimen to maximize efficacy and minimize the development of drug resistance.

Features

• Active pharmaceutical ingredient: Indinavir sulfate
• Available in 200 mg and 400 mg capsule formulations
• High specificity for HIV-1 protease enzyme
• Rapid absorption with peak plasma concentrations achieved within approximately 0.8 hours
• Administration requirements: Must be taken on an empty stomach or with a light, low-fat meal
• Metabolism primarily hepatic via cytochrome P450 3A4 isoenzyme
• Elimination half-life of approximately 1.8 hours in adults

Benefits

• Significantly reduces HIV viral load when used in combination therapy
• Increases CD4+ T-cell counts, improving immune function
• Delays progression to AIDS-defining illnesses
• Demonstrates high barrier to resistance when used appropriately in multidrug regimens
• Well-established safety profile with extensive clinical experience
• Contributes to improved long-term survival rates in HIV-positive patients

Common use

Indinavir is principally indicated for the treatment of HIV-1 infection in adults and pediatric patients aged 4 years and older, in combination with other antiretroviral agents. It is utilized as a component of combination antiretroviral therapy, which is the standard of care for HIV management. The medication may be prescribed for both treatment-naïve patients and those who have received previous antiretroviral treatment, though resistance testing is recommended prior to initiation in treatment-experienced individuals. Off-label uses may include post-exposure prophylaxis in certain circumstances, though this application requires careful risk-benefit assessment by a specialist.

Dosage and direction

The recommended adult dosage is 800 mg (two 400 mg capsules) administered orally every 8 hours. For pediatric patients aged 4 years and older, the dosage is based on body surface area (500 mg/m² every 8 hours) not to exceed the adult dose. Administration must occur either 1 hour before or 2 hours after a meal, though it may be taken with a light, low-fat snack (e.g., skim milk, toast with jelly, or corn flakes) to improve tolerability. Dosage adjustment is necessary in patients with mild to moderate hepatic impairment (600 mg every 8 hours); use is not recommended in severe hepatic impairment. Concomitant administration with drugs that induce or inhibit CYP3A4 may require dosage modifications.

Precautions

Patients should maintain adequate hydration (at least 1.5 liters daily) to reduce risk of nephrolithiasis. Monitor liver function tests, serum triglycerides, and blood glucose regularly. Use with caution in patients with hemophilia due to potential increased bleeding risk. May cause hyperbilirubinemia (mostly unconjugated), which is generally benign but may require monitoring. Consider alternative antiretroviral therapy in patients with known history of nephrolithiasis. Pregnancy category C: use only if potential benefit justifies potential risk to fetus. Not recommended for use during breastfeeding.

Contraindications

Hypersensitivity to indinavir or any component of the formulation. Coadministration with drugs highly dependent on CYP3A4 for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events: alfuzosin, amiodarone, ergot derivatives, lovastatin, simvastatin, pimozide, sildenafil (for pulmonary arterial hypertension), triazolam, oral midazolam, and quinidine. Concurrent use with rifampin is contraindicated. Severe hepatic impairment.

Possible side effect

Common adverse reactions (>10%) include nephrolithiasis/urolithiasis (12%), nausea (12%), abdominal pain (9%), vomiting (8%), headache (6%), and asthenia/fatigue (6%). Laboratory abnormalities may include hyperbilirubinemia (14%), elevated ALT/AST (5-6%), and lipodystrophy. Less frequent effects include blurred vision, dizziness, rash, metallic taste, thrombocytopenia, and hyperglycemia. Rare but serious side effects include acute hemolytic anemia, diabetes mellitus exacerbation, and hepatitis.

Drug interaction

Significant interactions occur with drugs that inhibit CYP3A4 (ketoconazole, itraconazole - reduce indinavir dose to 600 mg every 8 hours) or induce CYP3A4 (efavirenz - increase indinavir to 1000 mg every 8 hours). Avoid concurrent use with St. John’s wort. May increase concentrations of calcium channel blockers, immunosuppressants, and phosphodiesterase-5 inhibitors. Rifabutin dosage should be reduced by 50% when coadministered. Antacids should be administered at least 1 hour apart from indinavir.

Missed dose

If a dose is missed by more than 2 hours, skip the missed dose and resume the regular dosing schedule. Do not double the next dose. Maintaining consistent 8-hour intervals is crucial for maintaining therapeutic drug levels and preventing resistance development. Patients should be advised to set reminders to support adherence to the strict dosing schedule.

Overdose

Limited experience with overdose. Maximum reported single dose is 3200 mg. Treatment should consist of general supportive measures including monitoring of vital signs and observation of clinical status. Since indinavir is highly protein-bound, dialysis is unlikely to be beneficial. Management should focus on symptomatic treatment and supportive care. Contact poison control center for latest guidance.

Storage

Store at controlled room temperature 20-25°C (68-77°F). Keep container tightly closed and protect from moisture. Dispense in original container with desiccant. Do not remove desiccant from bottle. Keep out of reach of children and pets. Do not use after expiration date printed on packaging.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions should be made by qualified healthcare professionals based on individual patient characteristics. Always follow the prescribing information provided with the medication and consult appropriate clinical guidelines. Dosage may need adjustment based on renal function, hepatic function, drug interactions, and other individual factors.

Reviews

Clinical trials demonstrate indinavir’s efficacy in reducing viral load below detectable levels in approximately 60-80% of treatment-naïve patients when combined with two nucleoside reverse transcriptase inhibitors. Long-term observational studies show sustained virologic response in adherent patients. Specialist consensus acknowledges its historical importance in HAART regimens, though newer agents with improved dosing schedules and side effect profiles are often preferred today. Patient-reported outcomes indicate satisfactory viral suppression but note challenges with the three-times-daily dosing schedule and dietary restrictions.