Atazanavir / cobicistat

Atazanavir - cobicistat | Dosage | Use

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

Atazanavir / cobicistat is a combination of two drugs (atazanavir and cobicistat) used for the treatment of AIDS. Atazanavir is an inhibitor of the HIV protease enzyme while cobicistat is an inhibitor of cytochrome liver enzymes and acts to increase the effect of atazanavir. This combination is used in the treatment of AIDS, usually together with antiretroviral drugs.

Warnings and precautions

Atazanavir / cobicistat is contraindicated in the following conditions:

  • In patients with severe renal impairment
  • In patients with severe hepatic impairment
  • In patients who are allergic to any ingredient of the drug
  • In patients who are taking other medicines that can interact with atazanavir / cobicistat

Caution is also required in the following situations:

  • In patients with hemophilia
  • In patients who suffer or have suffered from hepatitis B or C
  • In patients with gallstones
  • In patients with severely impaired heart function or arrhythmias
  • In diabetics

Since Atazanavir / cobicistat may interact with a number of drugs, it is very important that you tell your doctor about all the medications that you are using.

Its use should be avoided in patients younger than 18 years.


Atazanavir / cobicistat exist in the form of film-coated tablets in a dose of 300/150 mg (300 mg of atazanavir and 150 mg of cobicistat).

Take one tablet of Atazanavir / cobicistat daily during your lunch, with plenty of liquid.

The treatment should last as long as your doctor recommends.

Note that Atazanavir / cobicistat is not a cure for AIDS. It only slows down AIDS progression and reduces the chance of transmitting the virus to others (but it does not eliminate chance completely).


The list of drugs that interact with Atazanavir / cobicistat drug is quite long:

  • Anti-epileptics, such as: carbamazepine, valproic acid, phenobarbital, and others. Concomitant use with these drugs reduces the concentration of Atazanavir / cobicistat in the blood, which reduces its effectiveness.
  • Drugs that lower the level of stomach acid, and are used for the treatment of acid reflux, heartburn and gastric ulcers, such as: omeprazole, lansoprazole, pantoprazole, esomeprazole, rabeprazole, ranitidine, cimetidine, and famotidine. The acidic environment of the stomach is essential for absorption of Atazanavir / cobicistat and by reducing the acidity in the stomach, these drugs reduce the absorption (utilization), and therefore the effectiveness of this drug.
  • Antimicrobial agents, such as: clarithromycin, erythromycin, azithromycin, and others. These drugs increase the level of Atazanavir / cobicistat in the blood and increase the risk of life-threatening arrhythmias.
  • Fentanyl (an opioid analgesic). Concomitant use of Atazanvir / cobicistat with this drug significantly increases the concentration of fentanyl in the blood, increasing the risk of serious adverse effects (respiratory depression and arrhythmias).
  • Corticosteroids, such as: methylprednisolone, fluticasone, budesonide and traimcinolone. Co-administration leads to an increased risk of side effects of corticosteroids.
  • Drugs used for heart disease treatment (beta-blockers and calcium antagonists), such as: bisoprolol, acebutolol, atenolol, timolol, propranolol, carvedilol, diltiazem, nifedipine, verapamil, and others. Concurrent use increases the risk of arrhythmia.
  • Drugs used for diarrhea treatment, such as: loperamid. Atazanavir / cobicistat significantly increases the concentration of loperamide in the blood, which increase the risk of side effects.
  • Statins (cholesterol-lowering drugs), such as: pravastatin, simvastatin, rosuvastatin, lovastatin, fluvastatin and atorvastatin. Atazanavir / cobicistat significantly increase the concentration of these drugs in the blood, which increases the risk of liver damage and severe muscle damage that leads to severe renal impairment!
  • Inhibitors of PDE-5 enzyme (drugs for erectile dysfunction treatment), such as: viagra, cilalis, kamagra and others.

Since this drug may interact with thousands of medicines, please tell your doctor about all the medicines you are taking, including herbal supplements and teas.

Side effects

Atazanavir / cobicistat can cause the following side effects:

  • Torsade de pointes (a very dangerous type of arrhythmia)
  • Hepatic jaundice, hyperbilirubinemia, and hepatitis
  • Chest pain
  • Sleep disorders
  • Inflammation of the pancreas
  • Enlargement of the spleen (splenomegaly)
  • Muscle atrophy
  • Neurological disorders (depression, confusion, agitation and amnesia)
  • Dyspnea and rapid breathing
  • Increased appetite and weight gain
  • Inflammation of the gallbladder
  • Skin rash
  • Itchy skin
  • Dry mouth
  • Sore throat
  • Swelling

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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