Sign up for our newsletter
Get health tips, wellness advice, and more

Thanks for signing up!
You've been added to our list and will hear from us soon.

See all Healthline's newsletters »

Generic Name:

ritonavir, Oral capsule

All Brands

  • Norvir
SECTION 1 of 4

Highlights for ritonavir

Oral capsule

Ritonavir is most often used to boost the effect of other human immunodeficiency virus (HIV) medications. It’s usually taken with other HIV drugs.


Ritonavir interacts with many medications. Always be sure to tell your doctor and pharmacist about any prescription and over-the-counter drugs, vitamins, and supplements you’re taking.


The dose is usually one or two tablets per day when taken as a booster. The dose may be up to 600 mg twice per day when given as a sole protease inhibitor.


You could experience liver or pancreas problems while taking this drug. Common side effects include diarrhea, skin tingling, and others.


Your doctor will check if ritonavir is working by monitoring your CD4 count (a type of white blood cell) and HIV virus count.


FDA Warning

This drug has a Black Box Warning. This is the most serious warning from the Food and Drug Administration (FDA). Though the medication can still be sold and used, a black box warning alerts doctors and patients to potentially dangerous effects.

Warning: This drug comes with possible drug-to-drug interactions leading to potentially serious and/or life-threatening reactions.

Taking ritonavir with some other drugs could cause serious side effects. These drugs include:

  • sedative hypnotics (sleeping pills)
  • antiarrhythmics (drugs to regulate your heart rhythm)
  • ergot alkaloid preparations (often used to treat migraines)

Ritonavir is processed through your liver. When it’s taken with other drugs that are processed in the liver, the drug levels may go up. This could lead to toxic effects. Always tell your doctor and pharmacist about all drugs you’re taking so they can catch any drug interactions.

Liver disease and pancreatitis

You could develop liver disease or pancreatitis while taking ritonavir. If you have nausea, vomiting, pain in your abdomen, and fatigue, call your doctor right away.

May cause allergic reactions

Call 9-1-1 or get to an emergency room if you develop:

  • hives
  • symptoms of bronchospasm, including breathing difficulty, wheezing, or coughing

May change heart rhythm

If you have heart disease, drug interactions with ritonavir are more likely to cause changes in your heart rhythm. If you feel changes to your heartbeat, such as palpitations, fluttering heartbeat, rapid heartbeat, or pulsations, call your doctor or 9-1-1.

What is ritonavir?

Ritonavir is a prescription drug. It’s available in these forms: oral tablet, oral capsule, oral solution.

Ritonavir is used as part of a combination therapy. That means you might need to take this drug in combination with other drugs to treat your condition.

Why it's used

Ritonavir is used in combination with other drugs to treat HIV infection. It’s most often used to boost the effect of other HIV drugs.

Ritonavir is approved for treating HIV in adults and children one month of age and older.

How it works

Ritonavir belongs to a class of drugs called protease inhibitors. Protease inhibitors block an HIV enzyme called protease. HIV needs this enzyme to copy itself and spread in your body. Blocking the enzyme helps prevent the HIV virus from replicating and spreading.

SECTION 2 of 4

ritonavir Side Effects

Oral capsule

Most Common Side Effects

The most common side effects that occur with ritonavir include:

  • diarrhea

  • nausea

  • vomiting

  • abdominal pain (upper and lower)

  • tingling of skin, fingers, or in the mouth

  • rash

  • fatigue

  • changes in body fat, such as increased fat on the back of your neck

  • increased cholesterol and triglycerides, which are checked by blood tests. If this happens, you may need to start a cholesterol-lowering drug.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • liver problems. Symptoms may include:

    • nausea
    • vomiting
    • pain in your stomach
    • yellowing of eyes or skin
    • fatigue
    • weakness
  • pancreatitis. Symptoms may include:

    • nausea
    • vomiting
    • upper abdominal pain
    • abdominal tenderness
  • allergic reaction. Symptoms may include:

    • difficulty breathing
    • wheezing
    • severe coughing
    • skin redness, blistering, welts, and hives
  • irregular or slow heartbeat. Symptoms may include:

    • trouble breathing
    • feeling weak or unsteady
  • spontaneous bleeding. If you have hemophilia, be aware that spontaneous bleeding could occur while you take ritonavir. You may require additional factor VIII (clotting protein). 

  • diabetes. Signs may include:

    • increased blood sugar
    • increased thirst
    • fatigue
    • mood changes
    • weight loss
  • symptoms of infections, such as fungal infections, pneumonia, or tuberculosis. These can be signs of immune reconstitution syndrome (IRS). In IRS, your recovering immune system may cause infections you’ve had in the past to return.

Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Ritonavir does not cause drowsiness.

Mild side effects may disappear within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 4

ritonavir May Interact with Other Medications

Oral capsule

Ritonavir can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Medications that might interact with this drug

Pain drugs
  • fentanyl
  • tramadol (Ultram)
  • meperidine (Demerol)
  • methadone

Antibiotics & other drugs to treat infections
  • metronidazole
  • clarithromycin
  • rifabutin
  • rifampin
  • quinine
  • bedaquiline

  • nefazodone
  • fluoxetine
  • paroxetine
  • amitriptyline
  • nortriptyline
  • bupropion
  • desipramine
  • trazodone

Human immunodeficiency virus (HIV) drugs
  • atazanavir (Reyataz)
  • darunavir (Prezista)
  • fosamprenavir (Lexiva)
  • indinavir (Crixivan)
  • saquinavir (Invirase)
  • tipranavir (Aptivus)
  • delavirdine (Rescriptor)
  • maraviroc (Selzentry)
  • raltegravir (Isentress)

Epilepsy drugs
  • carbamazepine
  • clonazepam
  • ethosuximide  
  • divalproex
  • lamotrigine
  • phenytoin

Antifungal drugs
  • ketoconazole
  • itraconazole
  • voriconazole

Blood thinner, or anticoagulant
  • warfarin

Cancer (chemotherapy) drugs
  • dasatinib
  • nilotinib
  • vincristine
  • vinblastine

Cholesterol-lowering drugs
  • atorvastatin (Lipitor)
  • rosuvastatin (Crestor)

Erectile dysfunction drugs
  • avanafil (Stendra)
  • sildenafil (Viagra)
  • tadalafil (Cialis)
  • vardenafil (Levitra, Staxyn)

Heart drugs

Heart drugs that regulate heart rhythm:

  • disopyramide
  • lidocaine
  • mexiletine 

Beta blockers: 

  • metoprolol
  • timolol

Calcium channel blockers: 

  • diltiazem
  • nifedipine
  • verapamil

Other heart drugs:

  • digoxin (Lanoxin)

Inhalers and Inhaled drugs
  • fluticasone
  • budesonide
  • salmeterol 

Mental health drugs
  • perphenazine
  • risperidone
  • thioridazine
  • lurasidone

Nausea-preventing drugs
  • dronabinol

Oral contraceptives
  • ethinyl estradiol

Post-transplant drugs (Immunosuppressants)
  • cyclosporine
  • tacrolimus
  • sirolimus (Rapamycin)

Sleeping pills and sedatives
  • buspirone
  • clorazepate
  • diazepam
  • estazolam
  • flurazepam
  • zolpidem

  • budesonide
  • dexamethasone
  • prednisone

Other Drugs
  • bosentan (Tracleer) for pulmonary arterial hypertension
  • disulfiram (Antabuse)
  • colchicine
  • methamphetamine (stimulant)
  • theophylline (bronchodilator)

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Ritonavir warnings
People with hemophilia

If you have hemophilia, be aware that spontaneous bleeding could occur while you take ritonavir. You may require additional factor VIII (clotting protein).

People with heart disease

If you have heart disease, you’re at increased risk of drug interactions that affect your heart. If you have an irregular or slow heartbeat after taking ritonavir, call 9-1-1 or go to the nearest emergency room.

People with diabetes

If you have diabetes, ritonavir may increase your blood sugar. Monitor your blood sugar carefully while on the drug.

People with past infection

Immune reconstitution syndrome (IRS) may occur. In IRS, your recovering immune system may cause infections you’ve had in the past to return. Call your doctor if you experience symptoms.

pregnant women
Pregnant women

Ritonavir is a pregnancy category B drug. That means two things: 

  1. Studies of the drug in pregnant animals have not shown risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show the drug poses a risk to the fetus.

Speak with your doctor if you’re pregnant or plan to become pregnant. Ritonavir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Women who are nursing

HIV can be passed through breast milk. The U.S. Department of Health and Human Services advises women with HIV not to breastfeed.

In addition, this drug may be passed through breast milk and could cause serious side effects in the baby.

For Children

Preterm Newborn Babies: The oral solution form of this drug shouldn’t be used in preterm newborns because it could be toxic. A safe and effective dose of the oral solution in preterm newborns hasn’t been established.

When to call the doctor

Call your doctor right away if you think you experience symptoms of worsening HIV, which include:

  • fever
  • weakness
  • chills
  • night sweats
  • sore throat
  • joint pain

If you experience worsening symptoms, you may need a different treatment.


Ritonavir can cause an allergic reaction. Symptoms may include:

  • rash
  • welts
  • breathing problems
  • anaphylaxis

Don’t take this drug again if you have ever had an allergic reaction to it before. Taking it again could be fatal.

SECTION 4 of 4

How to Take ritonavir (Dosage)

Oral capsule

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What Are You Taking This Medication For?

Human immunodeficiency virus (HIV)

Brand: Norvir

Form: Oral tablet
Strength: 100 mg
Form: Oral capsule
Strength: 100 mg
Form: Oral solution
Strength: 80 mg/mL
Adult Dosage (ages 18-64 years)
  • When used as a primary drug to treat HIV: 600 mg taken twice a day
  • When used to boost the effect of other HIV drugs: 100 mg once or twice a day
Child Dosage (ages 4 weeks-17 years)
  • The dose of ritonavir for children younger than 1 month is 350–400 mg per square meter of body surface area.
  • This dose is given twice per day with meals and shouldn’t exceed 600 mg twice per day.
  • Your child’s doctor will calculate the exact dose of ritonavir.
Senior Dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A normal adult dose may cause levels of the drug to be higher than normal. If you’re a senior, you may need a lower dose or you may need a different schedule.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Keeping HIV under control requires lifelong treatment. There can be serious health consequences if you don’t take this drug exactly how your doctor tells you.

If You Stop or Miss Doses

If you stop taking this medication, miss doses, or don’t take it on schedule, your HIV can become worse. You may have many more serious infections and HIV-related problems.

If You Don’t Take It on Schedule

Taking your drug at the same time every day increases your ability to keep the virus under control. If you don’t, you risk worsened infection.

What To Do if I Miss a Dose

If you forget to take your dose, take it as soon as you remember. If it's just a few hours until your next dose, wait and take a single dose at the usual time.

Take just one dose at a time. Never try to catch up by taking two tablets at once. This could result in toxic side effects.

How Can I Tell if the Drug Is Working?

To see how well the treatment is working, your doctor will check your:

  • virus count. A virus count measures the number of copies of the HIV virus in your body.
  • CD4 count. A CD4 count measures the amount of CD4 cells in your body. CD4 cells are white blood cells that fight infection. An increased CD4 count is a sign that your HIV treatment is working.

Ritonavir is a long-term drug.

Always take ritonavir with a meal

This will help to decrease nausea and may help you to absorb the drug better.

Ritonavir is a film-coated tablet and shouldn’t be crushed

There is an oral solution available if you’re not able to take the tablets.

Storage depends on the form of the drug

Store the tablet at or below 86°F (30°C). Exposure to temperatures up to 122°F (50°C) for seven days is reasonably safe. Keep ritonavir in its original bottle and away from light.

Ritonavir capsules should be stored in the refrigerator: between 36–46°F (2–8°C). As long as they’re used within 30 days, you can also store the capsules at room temperature 68–77°F (20–25°C).  Keep the capsules away from light and heat. Keep them tightly closed and store them in their original container.

Ritonavir solution should be stored at room temperature: 68–77°F (20–25°C). Don’t refrigerate the solution. Shake it well each time you take a dose. Use it by the expiration date on the bottle. Keep it in its original bottle. Keep it tightly closed and avoid exposing it to heat.

Note: Be careful of moist environments, including bathrooms. To keep drugs away from moisture, store them somewhere other than your bathroom and any other damp location. High humidity can reduce the effectiveness of ritonavir.

Clinical Monitoring

Liver function: Your doctor will check your liver function with blood tests before you take ritonavir and periodically during treatment. It's important to have a starting liver enzyme test to know what your usual enzymes are. Later tests will be compared to the first one to see if any changes in your liver enzymes have happened.

Some people may have changes in liver enzyme tests, which are used to measure damage to the liver. The damage can be very severe in some patients and can lead to death. You’re at higher risk if you have hepatitis B or hepatitis C.

Cholesterol levels: Your cholesterol and triglycerides may go up while you take ritonavir. Your doctor will check your cholesterol levels with a blood test.

Your doctor may also monitor your:

  • uric acid
  • fasting glucose
  • creatine phosphokinase (CPK), an enzyme found in your muscle, heart, and elsewhere

Not every pharmacy stocks this drug, so call ahead

If you only need a few tablets or capsules, you should call and ask if your pharmacy dispenses only a small number of tablets of capsules. Some pharmacies can't dispense only part of a bottle.

This drug is often available from specialty pharmacies through your insurance plan. These pharmacies operate like mail order pharmacies and ship the drug to you.

In larger cities, there will often be HIV pharmacies where you can have your prescriptions filled. Ask your doctor if there's an HIV pharmacy in your area.


Many insurance companies will require a prior authorization before they approve the prescription and pay for ritonavir.

Are There Any Alternatives?

There are several drugs and combinations that can treat HIV. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Show Sources

Content developed in collaboration with Susan J. Bliss, RPh, MBA

Medically reviewed by Alan Carter, PharmD and Stacey Boudreaux, PharmD on December 19, 2016

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.