Darunavir Ethanolate Tablets

Q1: What is Darunavir (Daruvir 800mg) used for?

Darunavir is a second-generation HIV protease inhibitor used for treatment-experienced patients with multidrug-resistant HIV, and increasingly as a first-line option. It retains activity against many PI-resistant HIV strains.

Q2: How does Darunavir overcome HIV resistance to earlier protease inhibitors?

Darunavir binds HIV protease with exceptional affinity and tightly fits the active site. It was designed to maintain binding even when common PI-resistance mutations are present, giving it a higher barrier to resistance than first-generation PIs like lopinavir.

Q3: Why must Darunavir be boosted with Ritonavir or Cobicistat?

Darunavir is heavily metabolised by CYP3A4 liver enzymes. Ritonavir 100mg inhibits CYP3A4, increasing Darunavir plasma levels 10–20 fold. Without boosting, Darunavir levels are too low for therapeutic effect. Cobicistat can alternatively be used as a booster.

Q4: What is the correct dose of Darunavir 800mg?

For treatment-naive or experienced patients with no darunavir resistance mutations: 800mg once daily + ritonavir 100mg once daily WITH FOOD. For patients with darunavir resistance mutations: 600mg twice daily + ritonavir 100mg twice daily WITH FOOD.

Q5: Why must Darunavir always be taken with food?

Food increases Darunavir bioavailability by approximately 30%. Taking on an empty stomach results in subtherapeutic drug levels, risking virological failure. Always take with a full meal.

Q6: What are the most common side effects?

Diarrhea, nausea, rash, headache, and fatigue are most common. Darunavir has a sulfonamide moiety — patients with sulfonamide allergy should be monitored for rash.

Q7: What is Stevens-Johnson syndrome and what triggers it?

Stevens-Johnson syndrome (SJS) is a rare but life-threatening severe skin reaction causing blistering and mucous membrane involvement. Any severe or spreading rash during Darunavir therapy requires immediate discontinuation and emergency medical evaluation.

Q8: What liver monitoring is required?

Liver function tests at baseline and every 3 months during treatment. Darunavir requires hepatic metabolism — patients with moderate to severe liver disease need dose adjustment or avoidance. HIV/HBV or HIV/HCV co-infected patients are at higher hepatotoxicity risk.

Q9: What drug interactions affect Darunavir/Ritonavir?

This is a strong CYP3A4 inhibitor combination with extensive interactions: statins (lovastatin, simvastatin contraindicated), rifampicin (contraindicated — major interaction), sildenafil, anticoagulants, and many others. Comprehensive drug interaction review is essential.

Q10: Can Darunavir be used during pregnancy?

Darunavir 600mg/ritonavir 100mg twice daily (not once-daily) is the recommended dose in pregnancy due to altered pharmacokinetics. It is included in pregnancy guidelines as an option — must be managed by HIV/OB specialist.

Q11: How should Daruvir 800mg be stored?

Store at room temperature below 30°C, away from moisture and light. Keep in original packaging out of reach of children. Do not use after the expiry date.

Q12: Do I need a prescription for Darunavir?

Yes. Darunavir requires specialist HIV prescribing, genotypic resistance testing to determine appropriate dosing, and regular viral load and liver function monitoring.