ritonavir at a glance
Medicine class
HIV protease inhibitor and pharmacokinetic enhancer
Licensed role
Boosts selected protease inhibitors within combination treatment for HIV-1 in adults and children aged 2 years and over
Food
Take with food
Important safety point
Ritonavir has many potentially serious interactions, including with prescribed, over-the-counter and herbal products
What is ritonavir used for?
The selected products are licensed as pharmacokinetic enhancers of co-administered protease inhibitors within combination antiretroviral treatment for HIV-1.
Treatment of HIV-1 in adults as part of an appropriate combination regimen.
Treatment of HIV-1 in children aged 2 years and over as part of an appropriate combination regimen.
Ritonavir is used to boost the accompanying protease inhibitor; the complete regimen must be selected by an HIV specialist.
How does ritonavir work?
Ritonavir inhibits HIV protease, an enzyme needed to produce mature infectious virus particles. In its usual boosting role, its more important effect is strong inhibition of CYP3A4-mediated metabolism, which raises and prolongs exposure to the accompanying protease inhibitor.
ritonavir preparations and strengths
Oral suspension
Route: Oral
Strengths: 100 mg
Tablet
Route: Oral
Strengths: 100 mg
How to take ritonavir
Follow the prescription and the instructions for the accompanying HIV medicine. Do not stop treatment without speaking to the HIV team, because interruptions can reduce viral control and encourage resistance.
Take ritonavir with food.
Swallow film-coated tablets whole; do not chew, break or crush them.
Mix the powder only with the supported soft foods or liquids described in the leaflet, and consume the entire prepared portion within 2 hours.
When measuring part of a prepared powder mixture, use the supplied oral syringe and follow the leaflet carefully.
The powder may be given through a suitable feeding tube after mixing with water according to the product instructions.
ritonavir side effects
Common or expected effects
- Nausea, vomiting, diarrhoea, abdominal discomfort or indigestion
- Headache, dizziness or tiredness
- Altered taste
- Tingling or numbness around the mouth or in the hands or feet
- Rash or itching
- Joint or back pain
Get urgent medical advice
- Severe allergic reaction, including facial swelling or anaphylaxis
- Severe blistering or peeling skin reactions
- Hepatitis or jaundice
- Pancreatitis, which may cause severe persistent abdominal pain
- Severe diarrhoea or vomiting causing dehydration or kidney problems
- Muscle inflammation, muscle breakdown or marked weakness
ritonavir in pregnancy
Available pregnancy experience, mainly involving ritonavir as a booster in combination treatment, has not shown a higher rate of birth defects than expected. It may be used when clinically needed. Anyone who is pregnant or planning pregnancy should have the complete HIV regimen reviewed by the specialist team and should not stop antiretroviral treatment without advice.
ritonavir while breastfeeding
Ritonavir is present in breast milk. The product information advises against breastfeeding during treatment. Current NHS information says formula feeding is the safest option for someone living with HIV, although breastfeeding may be possible in selected people with an undetectable viral load under close specialist monitoring; discuss feeding plans early with the HIV and maternity teams.
ritonavir interactions
Ritonavir strongly affects CYP enzymes and transport proteins, so a complete interaction check is required before starting, stopping or changing any medicine.
St John’s wort
Must not be combined because it can lower ritonavir exposure and reduce treatment effectiveness.
Simvastatin or lovastatin
Combination is contraindicated because markedly increased statin exposure can cause myopathy or rhabdomyolysis.
Oral midazolam, triazolam and certain other sedatives
Combination is contraindicated because profound or prolonged sedation and respiratory depression may occur.
Common questions about ritonavir
Answers are fully visible for fast scanning and source review.
Why is ritonavir added to another HIV treatment?
It blocks the metabolism of selected protease inhibitors, increasing and prolonging their exposure. This is called pharmacokinetic boosting.
Does ritonavir treat HIV on its own?
The selected products are licensed for use with another protease inhibitor as part of combination HIV treatment, not as stand-alone therapy.
Should ritonavir be taken with food?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.