Although it was originally developed for use as a protease inhibitor in its own right, today ritonavir is mainly used in low doses to boost the effect of other protease inhibitors.

Basic info

Generic name ritonavir
Brand name Norvir
Also known as RTV
Drug class Protease Inhibitors
Pediatric dosing? Available in doses suitable for children and/or young people.
Availability in Australia Available on the Pharmaceutical Benefits Scheme (PBS) through S100 prescribers since 1996
This drug may be available through clinical trials in Australia.
You may be able to import this drug from overseas for your personal use.
Formulation 100mg tablet x 30, and also in liquid form: ritonavir liquid: 600 mg/7.5 mL oral liquid, in 90 mL bottles

Taking it

Like most anti-HIV drugs, ritonavir must be taken in combination with other drugs to be completely effective. Commonly, ritonavir is combined with one other nucleoside (NRTI) drug and either a protease inhibitor or non-nucleoside, although other combinations are sometimes used. Your doctor will advise you on the right combination of drugs to suit your circumstances.


Mainly used in small doses (100mg/200mg) in combination with other PIs to boost the levels of other PI's.  May also be used to boost the levels of other HIV treatments.

Regardless of what you read on this website or elsewhere, you should always take your medications according to your doctor's instructions. If you're unsure, speak to your doctor or pharmacist.

With or without food

ritonavir should be taken with food

Side effect

All drugs can produce side effects in some people. These may be mild, moderate or severe, so you should be aware of potential side effects before starting any drug, and speak to your doctor if you experience side effects that concern you.

Interactions with other drugs

As well as boosting the levels of other HIV treatments ritonavir can also boost the levels of certain other medications, supplements and recreational drugs. Ritonavir can boost the levels of medications used to treat erectile dysfunction (Viagra, Cialis, Levitra), medications to treat tuberculosis (TB), to treat problems with heart rhythm (antiarrhythmics) and for migraine headaches. Interactions are also possible with several antihistamines (allergy medications), sedatives, drugs to lower cholesterol and anti-fungal drugs. Some birth control pills may not work if you are taking ritonavir. Ritonavir also lowers blood levels of methadone, and also interacts with buprenorphine, or 'bupe'. Watch for signs of excessive sedation if you take ritonavir with buprenorphine. Ritonavir can boost the levels of certain recreational drugs especially amphetamines including methamphetamine (crytsal, crystal meth, meth, tina), ecstacy, cocaine, MDMA and others. Taking amphetamines with ritonavir can cause serious health issues and even permanent heart disease. Talk to your doctor if there is a chance that you could take amphetamines whilst taking ritonavir. It is important that you have a doctor that you can discuss all aspects of your health with openly and without fear of judgement. Your doctor may want to discuss alternative treatment combinations as well as discuss your recreational drug use. The herb St. John's Wort (hypericum) lowers the blood levels of protease inhibitors. Do not take St John's Wort with ritonavir, or any other HIV treatments as St John's Wort can lower the levels of HIV treatments so that they are unable to work effectively against HIV, and also risk developing resistance to your HIV treatments.