Cobicistat – Oral Route

Cobicistat is part of a group of medicines called pharmacokinetic enhancers, which work by reducing the breakdown of other drugs in the body to increase their effectiveness.


Cobicistat is a medication that is prescribed to treat patients with human immunodeficiency virus (HIV). Its purpose is to increase the impact of the atazanavir or darunavir, which are common long-term treatments given to patients to control their conditions. Atazanavir and darunavir are antiviral drugs that prevent HIV cells from multiplying. They are not cures for the condition. Using cobicistat can prolong the impact of these antiviral drugs, enabling them to combat call multiplication for longer. Using cobicistat along with atazanavir or darunavir provides a more aggressive combination for controlling the HIV virus.

Cobicistat is part of a group of drugs called pharmacokinetic enhancers. These drugs work by interfering with and reducing the breakdown of other drugs in the body (such as atazanavir or darunavir), thus increasing the level of these substances in the blood and making them more impactful.

Cobicistat is not a treatment for HIV or AIDS; it merely helps to improve the effectiveness of other drugs. Therefore, it is not prescribed on its own, and maybe one of many drugs prescribed for HIV sufferers.

HIV is a chronic virus that impacts the cells in the human immune system, therefore reducing its effectiveness when fighting diseases and infections. The condition can lead to acquired immune deficiency syndrome (AIDS). AIDS is the term given to any life-threatening infections that a patient may acquire as a result of a damaged immune system caused by HIV. Although there is no cure for HIV, the condition can be managed successfully with drug combinations such as antivirals and pharmacokinetic enhancers, enabling the patient to live a long and full life.

Cobicistat is provided in the form of a tablet, to be consumed orally. Cobicistat is also sold and marketed under the brand name Tybost in the United States.

Conditions treated

  • Human immunodeficiency virus (HIV)
  • Acceleration of atazanavir or darunavir

Type of medication

  • Tablet, for oral consumption

Side effects

Although HIV medications like cobicistat can help you live longer and enjoy a normal, healthy life, there may be some side effects. These are particularly common in the beginning stages of your treatment, and may be a result of the body adapting to the substance being in the system. These symptoms usually subside, but you should tell your doctor if they persist. Common side effects of cobicistat include:

  • Nausea and vomiting, or pain in the abdomen
  • Excessive tiredness, weakness or drowsiness
  • Diarrhea or problems passing bowel movements
  • Fever, chills, and symptoms of the common cold or flu
  • Pain in the muscles or bones
  • Dizziness, fainting, light-headedness or faintness
  • Changes in sleep patterns, such as inability to sleep or suffering from interrupted sleep (insomnia)
  • Headache, which can persist for several days

You should contact your doctor straight away if you are worried about any side effects you may be experiencing as a result of taking cobicistat. If any of the above common side effects persist, they could be a sign of a more serious underlying condition. Likewise, if you notice any of the below symptoms, you should seek medical assistance immediately:

  • Jaundice (yellow coloring of the skin and eyes)
  • Swelling, particularly in the lips, face, eyes, throat or tongue
  • Weak feeling in the bones

Long-term side effects can also occur as a result of taking cobicistat with other HIV medications. These conditions may not appear at first, and patients may wait years before they notice any symptoms of the following:

  • Kidney issues, including failure
  • Heart disease or cardiac arrest
  • Diabetes (type 2)
  • Osteoporosis (brittle bones)
  • Liver issues, including failure
  • Lipodystrophy (change in how the body stores and breaks down fat)
  • Psychiatric effects, such as mood changes, depression, anxiety, confusion or irritability
  • Hyperlipidemia (increase in fat in the bloodstream)

If any of these conditions are detected throughout your lifetime, you may see your prescription altered – either of your cobicistat or any of your other HIV medications. You may also need to stop taking the medication if your side effects are too severe.


Cobicistat is supplied as a tablet, with each one containing 150 mg of the substance. Patients should take one tablet per day at the same time as taking atazanavir or darunavir. This is very important in order to maximize the effectiveness of cobicistat in accentuating the impact of atazanavir or darunavir shortly after they enter the body.

You should take each dose at the same time each day, and take all tablets with a meal.

You should always stick to the dosage prescribed by your doctor, which will have been set for ensuring maximum effectiveness. Do not attempt to increase the dose yourself; taking more tablets will not increase the effectiveness of atazanavir or darunavir any further and could lead to symptoms of overdose.

Cobicistat works best when you stick to your regular doses. If you miss a dose, you should take it within 12 hours of it being missed. However, if more than 12 hours has passed, skip the dose and take the next one at the normal time. You should not double doses to make up for missed pills.

Major drug interactions

There are a large number of drugs that have been found to have an interaction with cobicistat. Drug interactions can happen between any medications that you are taking. Taking some combinations together may lead to increased side effects, dangerous health conditions, or could impact the effectiveness of the medications in treating your conditions. Therefore, you should tell your doctor about any form of medication you may already be taking before starting a course of cobicistat. Below are the 201 generic drugs that have a major reaction with cobicistat. Equally, if you are using a branded drug that contains any of the below, let your doctor know.

  • abemaciclib
  • acalabrutinib
  • acetaminophen, caffeine, chlorpheniramine, hydrocodone, phenylephrine
  • acetaminophen, hydrocodone
  • acetaminophen, oxycodone
  • alfentanil
  • alfuzosin
  • aminophylline, ephedrine, guaifenesin, phenobarbital
  • aminophylline, ephedrine, phenobarbital, potassium iodide
  • amiodarone
  • apixaban
  • artemether, lumefantrine
  • aspirin, hydrocodone
  • aspirin, oxycodone
  • atropine, hyoscyamine, phenobarbital, scopolamine
  • atropine, phenobarbital
  • avanafil
  • axitinib
  • azelastine, fluticasone nasal
  • belladonna, caffeine, ergotamine, pentobarbital
  • belladonna, ergotamine, phenobarbital
  • bepridil
  • bosentan
  • bosutinib
  • brexpiprazole
  • brigatinib
  • brompheniramine, hydrocodone, phenylephrine
  • brompheniramine, hydrocodone, pseudoephedrine
  • budesonide
  • budesonide, formoterol
  • bupivacaine, fentanyl
  • bupivacaine, lidocaine, triamcinolone
  • butorphanol
  • caffeine, ergotamine
  • carbamazepine
  • carbinoxamine, hydrocodone, phenylephrine
  • carbinoxamine, hydrocodone, pseudoephedrine
  • cariprazine
  • ceritinib
  • chlorpheniramine, guaifenesin, hydrocodone, pseudoephedrine
  • chlorpheniramine, hydrocodone
  • chlorpheniramine, hydrocodone, phenylephrine
  • chlorpheniramine, hydrocodone, pseudoephedrine
  • cilostazol
  • cisapride
  • cobimetinib
  • colchicine
  • colchicine, probenecid
  • conivaptan
  • copanlisib
  • crizotinib
  • cyclosporine
  • daclatasvir
  • darifenacin
  • dasatinib
  • deflazacort
  • dexbrompheniramine, hydrocodone, phenylephrine
  • dexchlorpheniramine, hydrocodone, phenylephrine
  • dextromethorphan, quinidine
  • dihydroergotamine
  • diphenhydramine, hydrocodone, phenylephrine
  • disopyramide
  • docetaxel
  • dronedarone
  • droperidol, fentanyl
  • dutasteride, tamsulosin
  • dyphylline, ephedrine, guaifenesin, phenobarbital
  • edoxaban
  • elbasvir, grazoprevir
  • eletriptan
  • eliglustat
  • eluxadoline
  • enzalutamide
  • ephedrine, phenobarbital, potassium iodide, theophylline
  • ephedrine, phenobarbital, theophylline
  • eplerenone
  • ergonovine
  • ergotamine
  • erythromycin
  • erythromycin, sulfisoxazole
  • eszopiclone
  • everolimus
  • ezetimibe, simvastatin
  • fentanyl
  • fentanyl, ropivacaine
  • fesoterodine
  • flecainide
  • flibanserin
  • fluticasone
  • fluticasone nasal
  • fluticasone, salmeterol
  • fluticasone, umeclidinium, vilanterol
  • fluticasone, vilanterol
  • fosphenytoin
  • guaifenesin, hydrocodone
  • guaifenesin, hydrocodone, pheniramine, phenylephrine, phenylpropanolamine
  • guaifenesin, hydrocodone, pheniramine, phenylpropanolamine, pyrilamine
  • guaifenesin, hydrocodone, phenylephrine
  • guaifenesin, hydrocodone, pseudoephedrine
  • guanfacine
  • halofantrine
  • homatropine, hydrocodone
  • hydrocodone
  • hydrocodone, ibuprofen
  • hydrocodone, pheniramine, phenylephrine, phenylpropanolamine, pyrilamine
  • hydrocodone, phenylephrine
  • hydrocodone, phenylephrine, pyrilamine
  • hydrocodone, phenylpropanolamine
  • hydrocodone, potassium guaiacolsulfonate
  • hydrocodone, potassium guaiacolsulfonate, pseudoephedrine
  • hydrocodone, pseudoephedrine
  • hydrocodone, pseudoephedrine, triprolidine
  • hyoscyamine, phenobarbital
  • ibrutinib
  • ibuprofen, oxycodone
  • iloperidone
  • irinotecan
  • irinotecan liposomal
  • isavuconazonium
  • isoniazid, pyrazinamide, rifampin
  • isoniazid, rifampin
  • ivabradine
  • ivacaftor
  • ivacaftor, lumacaftor
  • letrozole, ribociclib
  • levomethadyl acetate
  • lomitapide
  • loperamide
  • loperamide, simethicone
  • lovastatin
  • lovastatin, niacin
  • lurasidone
  • macitentan
  • methylergonovine
  • methylprednisolone
  • methysergide maleate
  • midazolam
  • midostaurin
  • mifepristone
  • mitotane
  • naloxegol
  • naloxone, oxycodone
  • naltrexone, oxycodone
  • neratinib
  • niacin, simvastatin
  • nilotinib
  • nimodipine
  • olaparib
  • osimertinib
  • oxycodone
  • palbociclib
  • panobinostat
  • pazopanib
  • phenobarbital
  • phenytoin
  • pimavanserin
  • pimozide
  • primidone
  • propafenone
  • quetiapine
  • quinidine
  • ranolazine
  • red yeast rice
  • ribociclib
  • rifabutin
  • rifampin
  • rifapentine
  • riociguat
  • rivaroxaban
  • ruxolitinib
  • salmeterol
  • sildenafil
  • silodosin
  • simeprevir
  • simvastatin
  • simvastatin, sitagliptin
  • sirolimus
  • solifenacin
  • sonidegib
  • st. john's wort
  • suvorexant
  • tamsulosin
  • temsirolimus
  • thioridazine
  • ticagrelor
  • tofacitinib
  • tolvaptan
  • toremifene
  • trabectedin
  • triamcinolone
  • triazolam
  • valbenazine
  • vardenafil
  • venetoclax
  • vinblastine
  • vincristine
  • vincristine liposome
  • vinorelbine
  • vorapaxar


Other diseases or conditions

If you suffer from any other conditions, you should speak to your doctor for advice on using cobicistat. The drug has been found to decrease creatinine clearance, so your doctor may wish to alter your dose if you have suffered from renal dysfunction, or are vulnerable to the condition. Patients should be monitored closely or periodically for renal safety.

Multivitamins, minerals and supplements

If you are taking any supplements or multivitamins, you should also make a note of these and discuss them with your doctor. There are some herbs and vitamins that can cause a major reaction with cobicistat, so you may need to stop taking them before starting a treatment course. St. John’s Wort is one that should not be taken at the same time as cobicistat; St. John’s Wort has been found to decrease the levels of cobicistat in the blood, therefore reducing the effectiveness of the drug.

Kidney complications

When taking cobicistat, there is the risk of developing kidney problems, or making existing kidney conditions worse. There are certain other medications that, when taken with cobicistat, can significantly increase the risk of kidney problems – occasionally leading to kidney failure. A patient’s kidneys should be checked thoroughly by a doctor before commencing treatment.


This medication is not suitable for babies under the age of three months. It may be used by children, but the dosage prescribed may be adjusted according to the age and medical history of the child.


You should take care to store your tablets as per the instructions on the label. Always keep them at room temperature (20 to 25 degrees centigrade) and in dry conditions. Do not store them in rooms that can become damp (such as the bathroom) and do not store in direct sunlight or too close to radiators.

Always keep your medication in a safe place, and in the original packaging with which it was supplied. Keep all medication containers tightly shut – locked if possible – to prevent access by children and pets.

If you discover your cobicistat medication is out of date, do not use it. It may be less effective, or may cause unpleasant side effects. Instead, throw it away safely by following the disposal guidelines issued by the FDA.


When used in conjunction with other HIV drugs, cobicistat has been found to be highly effective at helping to increase their effectiveness and contribute towards a long and healthy lifespan for the HIV sufferer. It is a fast-emerging drug, due to the fact that a large number of recent clinical trials have found it to be relatively safe and highly tolerated in many patients. As a result, it is becoming an alternative treatment to the commonly prescribed ritonavir for improving the effectiveness of other HIV medications.

Cobicistat is also increasingly becoming a preferred choice as it has a lower potential for interactions with other drugs than its counterparts. Therefore, it offers the patient more freedom in terms of taking other medicines. The risk of side effects has also been found to be slightly lower than that of its counterparts.

Despite its advantages, there are still a number of potential hazards that users of cobicistat should be aware of. This includes the risk of kidney complications, particularly in patients that are taking certain other medications, or who have suffered kidney problems in the past. Patients that are new to cobicistat should be monitored closely for signs of adverse reactions. However, checks on the kidneys should be performed regularly, as many patients do not experience signs of kidney complications until years later.

Although its potential to interact with other drugs is lower than that of some other HIV medications, there are still a large number of drugs that it is dangerous to take with cobicistat. Therefore, patients should always tell their doctors about any other medications they are taking for any other conditions - this includes over the counter medications as well as any herb supplements, vitamins or minerals. Likewise, patients should explain any other conditions that they have, or have suffered from in the past, so that the healthcare professional can determine the safest and most effective long-term treatment for HIV.

This is very important, as getting the drug combination for HIV right sooner will increase the patient's chance of living a normal lifespan without contracting any conditions that could be classed as AIDS.

If taken correctly and according to the manufacturer’s instructions, cobicistat can be a valuable addition to most HIV treatment plans. It has been found to positively impact other HIV medications, leading to more certainty of a long and healthy life for the patient.