Pharmacology · HIV protease inhibitors (PIs)
Lopinavir/ritonavir !
A fixed combination of lopinavir with ritonavir as booster. Widely used in children and second line; causes diarrhoea and raises lipids.
Updated 2026-11-01
Also called: LPV/r
The figure shows lopinavir in the active site of wild-type HIV-1 protease.
Mechanism of action
Lopinavir fills the HIV protease active site and prevents virus maturation. It is metabolised by CYP3A; the ritonavir in the tablet blocks that metabolism and keeps lopinavir at effective levels.
- Ritonavir inhibits CYP3A4 and raises lopinavir
- Lopinavir binds the protease active site
- Virions come out immature
Pharmacokinetics
- Metabolism
- Lopinavir: CYP3A, inhibited by the ritonavir in the combination
Indications
- HIV-1 infection in adults and children, combined with other antiretrovirals HIV infection and AIDS →
Adverse effects
Common
- Diarrhoea (common), nausea, vomiting
- Raised triglycerides and cholesterol
Contraindications
- Drugs highly dependent on CYP3A with serious risk if raised
- Strong inducers such as rifampicin or St John's wort
Key interactions
- Other QT-prolonging drugs or hypokalaemia
- Higher risk of torsade de pointes
- Statins cleared by CYP3A
- Risk of myopathy
What is monitored
- Lipids before starting and regularly
- Glucose and liver tests
- ECG if there is long-QT risk
Administration and safety
- By mouth; tablets are swallowed whole
- The oral solution contains ethanol and propylene glycol: it is not used in preterm newborns right after birth
- In children, check the ordered product and volume
- Keep a full list of medicines and herbal products and review it with pharmacy before any new drug
Nursing care
- Watch for diarrhoea and hydration
- Check lipids and glucose
- In children, confirm gestational age and weight before the oral solution
- Review interactions before any new drug
Pregnancy and breastfeeding
Antiretroviral treatment in pregnancy protects the mother and lowers HIV transmission to the baby; the treating team chooses the regimen.
Test yourself
Think of the answer, then tap the question to see it.
Why is lopinavir always sold with ritonavir?
Because lopinavir is cleared by CYP3A, and ritonavir, by inhibiting that enzyme, raises and prolongs its levels.
Why is the oral solution not used in preterm newborns?
It contains ethanol and propylene glycol, which preterm babies cannot metabolise well: risk of serious toxicity.
Which gut adverse effect is most common?
Diarrhoea.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - LOPINAVIR AND RITONAVIR tablet, film coated (DailyMed (U.S. National Library of Medicine), 2026); Lopinavir and Ritonavir: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.