Darunavir: what it does and how to use it safely

Darunavir is a strong HIV protease inhibitor that helps stop the virus from making new infectious copies. It’s often used when people need a robust option—especially after other drugs haven’t worked well. That’s useful, but darunavir only does its job if you take it the right way and watch for interactions.

How darunavir works and common dosing

Darunavir blocks HIV protease, an enzyme the virus needs to mature. Doctors usually give darunavir together with a booster drug—ritonavir or cobicistat—which raises darunavir levels in your blood. Typical adult dosing is 800 mg darunavir plus 100 mg ritonavir once daily with food, or 600 mg darunavir plus 100 mg ritonavir twice daily for some resistant cases. Don’t switch doses without talking to your prescriber.

Always take darunavir with a meal. Food helps the body absorb the drug and keeps blood levels steady. If you miss a dose, take it as soon as you remember unless the next dose is near; don’t double up to catch up without checking with your provider.

Side effects, interactions, and practical safety tips

Common side effects include nausea, diarrhea, headache, and rash. Some people see changes in cholesterol, blood sugar, or liver tests. If you notice jaundice, severe stomach pain, or a spreading rash, contact your healthcare team right away. Those may be signs of liver trouble or a serious allergic reaction.

Darunavir interacts with many drugs because it affects CYP3A4 in the liver. Avoid or adjust doses of some statins, benzodiazepines, certain heart rhythm drugs, and St. John’s wort. Tell every provider and your pharmacist you’re on darunavir so they can check for interactions. If you use recreational drugs or herbal supplements, mention them too—they matter.

Monitor regularly. Your clinic will likely check viral load, liver enzymes, lipids, and blood sugar after starting darunavir. These tests help catch side effects early and confirm the drug is working. Keep those follow-up appointments and bring a list of all medicines you take.

Pregnancy and breastfeeding: darunavir may be used in pregnancy but talk with your obstetrician and HIV specialist. They’ll weigh benefits and risks and adjust doses if needed. Don’t stop darunavir during pregnancy without medical advice.

Resistance can develop if doses are missed. Consistent daily use is the best way to keep the virus suppressed and prevent resistance. If you struggle with side effects or adherence, ask your provider about support options—pill boxes, reminders, or different regimens might help.

Bottom line: darunavir is powerful but needs careful use—take it with food, watch for interactions, attend monitoring visits, and speak up about side effects. Your healthcare team can help tailor the plan so the drug works for you without unnecessary risks.