Indications
- HIV-1 infection, always together with other HIV medicines. Today it is mostly used in a low dose as a “booster” that raises the levels of other HIV protease inhibitors such as Lopinavir, Darunavir or Atazanavir.
- It is also packed together with Nirmatrelvir for the treatment of COVID-19 in people at high risk of severe illness.
It is prescribed and monitored by an HIV or infectious disease specialist.
How It Works
Ritonavir is a protease inhibitor, which means it blocks an enzyme HIV needs to make new working virus particles. In low doses its main job is to slow the liver’s breakdown (through the CYP3A4 enzyme) of the medicine it is given with, so that medicine stays at effective levels in the blood. It does not cure HIV.
Dosage and Administration
- Take exactly as prescribed. As a booster it is commonly 100 mg once or twice a day, taken at the same time as the other HIV medicine.
- Take with food. Swallow tablets whole; do not chew, break or crush.
- For COVID-19 it is taken only as part of the combined pack, for 5 days, as prescribed.
- Children: as prescribed by the specialist, based on weight or body size.
- Do not stop or skip doses, as this can let HIV become resistant to treatment.
Interactions
Ritonavir interacts with many medicines, and some combinations are dangerous. Always check with your doctor or pharmacist before starting any new medicine, herbal product or supplement.
- Must not be combined with medicines such as Amiodarone, Simvastatin, Lovastatin, Alfuzosin, Ergotamine, Pimozide, Lurasidone, oral Midazolam, Triazolam, Rifampicin or St John’s wort.
- It raises the levels of many medicines, including some heart, blood pressure, cholesterol, sleeping, seizure and erectile dysfunction medicines, and blood thinners; doses may need changing.
- Inhaled or nasal steroids such as Fluticasone can build up and cause steroid side effects.
- It can make hormonal birth control less effective; use a barrier method as well.
Contraindications
- Allergy to ritonavir or any ingredient of the product.
- Severe liver disease.
- Use with any of the medicines that must not be combined with it (see Interactions).
Side Effects
Common: nausea, vomiting, diarrhoea, stomach pain, taste changes, tingling or numbness around the mouth or in the hands and feet, tiredness, rash, and raised cholesterol, triglycerides, blood sugar or liver enzymes.
Get urgent medical help if you have:
- Severe stomach pain spreading to the back, with nausea and vomiting (possible pancreatitis).
- Yellow skin or eyes, dark urine or pale stools.
- A severe skin rash with blistering, peeling or mouth sores, or swelling of the face, lips or throat.
- Fainting, a very slow, fast or irregular heartbeat.
Pregnancy and Lactation
Ritonavir is used in pregnancy as part of HIV treatment when the specialist decides it is the right choice; continuing effective treatment helps protect the baby from HIV. Advice on breastfeeding for mothers with HIV depends on the treatment and local guidance, so discuss it with your HIV specialist.
Precautions and Warnings
- Liver tests, blood fats and blood sugar are checked regularly; extra care with hepatitis B or C.
- People with haemophilia may bleed more easily.
- Tell the doctor about heart rhythm problems, diabetes or pancreatitis.
- As the immune system recovers, old infections may flare up; report any new symptoms.
- Treatment greatly lowers but does not alone remove every risk of passing HIV on; follow your specialist’s advice.
Overdose
Overdose can cause tingling, nausea, vomiting and effects on the heart and liver. Go to the nearest hospital straight away and take the pack with you.
Therapeutic Class
Antiretroviral medicine; HIV protease inhibitor and pharmacokinetic enhancer (booster).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Keep in the original container.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.