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Drug interactions between Norvir and Prezcobix

Results for the following 2 drugs:
Norvir (ritonavir)
Prezcobix (cobicistat/darunavir)

Interactions between your drugs


ritonavir cobicistat

Applies to: Norvir (ritonavir) and Prezcobix (cobicistat / darunavir)

Cobicistat is a medication used to boost the effects of some medications that treat HIV infection. However, using cobicistat together with other HIV medications, such as ritonavir, may alter the blood levels and effects of both medications. Using ritonavir with cobicistat may reduce or increase blood levels of cobicistat. Reduced blood levels of cobicistat may make cobicistat less effective and may cause overall HIV treatment to be less effective. Cobicistat may increase blood levels of ritonavir which may increase the risk of side effects. Talk to your doctor or pharmacist if you have any questions on how to use these medications properly. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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Drug and food interactions


ritonavir food

Applies to: Norvir (ritonavir)

Ritonavir should be taken with food to lessen gastrointestinal side effects. It is important that you take this medication exactly as prescribed by your doctor. Do not change your treatment or stop treatment without first talking to your doctor.

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darunavir food

Applies to: Prezcobix (cobicistat / darunavir)

Food can enhance the levels of darunavir in your body. Take darunavir with food. The type of food does not matter. This will make it easier for your body to absorb the medication. Swallow the whole tablets with a drink such as water or milk. Do not chew the tablets. Darunavir must be always be taken together at the same time as another medication called ritonavir (Norvir).

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Therapeutic duplication warnings

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.


Antiviral boosters

Therapeutic duplication

The recommended maximum number of medicines in the 'antiviral boosters' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'antiviral boosters' category:

  • Norvir (ritonavir)
  • Prezcobix (cobicistat/darunavir)

Note: The benefits of taking this combination of medicines may outweigh any risks associated with therapeutic duplication. This information does not take the place of talking to your doctor. Always check with your healthcare provider to determine if any adjustments to your medications are needed.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.