Cobicistat - Precautions | Dosage | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Cobicistat is a drug from the group of inhibitors of CYP3A and is used to enhance the effects of drugs used to treat AIDS (e.g. atazanavir and darunavir). CYP3A enzyme is responsible for the metabolism and elimination of atazanavir and darunavir from the body. By blocking this enzyme, Cobicistat boosts the effect of these drugs.

Cobicistat itself has no effects against AIDS (HIV) but enhances the effects of other drugs used for its treatment.

There are also fixed combinations of Cobicistat with atazanavir and darunavir. A combination of Cobicistat with atazanavir is known as Evotaz and a combination of Cobicistat with darunavir is known as Prezcobix.


Very important note: Since Cobicistat affects the metabolism of a large number of drugs (affects almost 50% of all existing drugs) which lead to an increase in concentration of these drugs in the blood and thus can increase risk of side effects, the most important thing before you start taking Cobicistat is to inform your doctor about all the medicines you are taking.

Its use is not recommended in patients who have kidney problems because this medicine works by inhibiting renal tubular secretion and can damage kidney function.

Cobicistat, pregnancy and breastfeeding

Since Cobicistat is used in patients with AIDS, these patients must not allow themselves to become pregnant because the baby will automatically get AIDS from the mother.

Cobicistat belongs to the group B (according to the FDA), which means that its use in animals showed no adverse effects on the fetus, but there are no controlled studies in humans.

Never breastfeed your baby if you have AIDS, because the virus can be transmitted to infants.


The usual dose in the treatment of AIDS is 150 mg once a day, together with atazanavir (at a dose of 300 mg) or darunavir (at a dose of 800 mg).

Swallow the tablet whole, after meal, with sufficient liquid.

If you have been taking a combination of ritonavir / atazanavir (at a dose of 100 mg / 300 mg), you cannot use Cobicistat instead of ritonavir without prior consultation with your doctor.

FDA has not approved the use of this drug in pediatric patients.


As noted above, a large number of drugs can interact with Cobicistat, and it is very important that you tell your doctor about all the medications you are taking, including those obtained without a prescription and herbal preparations.

It would be wise to make a list of all medications you are taking and when you need to change something in that list, you should not do it without your doctor's advice.

In the table below, you can find examples of drugs that interact with Cobicistat and the result of that interaction.

Table 1: Interactions of Cobicistat with other drugs

Drugs that interact with Cobicistat Consequence of interaction
Corticosteroids, such as: Traimcionolone, Methylprednisolone, Fluticasone Increased risk of side effects, such as: High blood pressure, Edema, high blood sugar, increase in body weight, depression
Opioid analgesics, such as: Fentanyl, Oxycodone, Alfentanyl Side effects, such as: Difficulty breathing, fainting, slow heartbeat
Antiarrhythmics, such as: Amiodarone Side effects, such as: Irregular heartbeat
Alpha blocking agents, such as: Doxazosin, Alfuzosin Sudden drop in blood pressure
Anti-epileptics, such as: Carbamazepine, Phenobarbital Decrease of effectiveness of Cobicistat
Drugs for treatment of migraine, such as: Ergotamine, Dihydroergotamine Increased risk of the following adverse effects: Vasoconstriction, increased blood pressure, heart attack, stroke.
Colchicine, a drug used to treat gout Increased risk of serious side effects

Above are listed only some interactions, but keep in mind that Cobicistat may interact with more than 5,000 medications.

Side effects

The most dangerous side effect is an allergic reaction. If you notice symptoms of an allergy (swelling of the face, swelling of the tongue or difficulty breathing), you should immediately contact your doctor.

Other side effects include:

  • Mild damage to the liver with the appearance of jaundice
  • Mild renal impairment accompanied by increase in creatinine levels
  • Blood in the urine (linked to renal impairment)
  • Drowsiness
  • Icterus of an eye
  • Digestive disorders
  • Vomiting blood
  • Insomnia
  • Depression

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.

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