Ritonavir

Ritonavir is a prescription medication used to treat human immunodeficiency virus (HIV) infections in adults and children. Ritonavir belongs to a group of drugs called HIV protease inhibitors, which decrease the amount of HIV in the blood.

This medication comes in capsule, tablet, and oral solution forms and is taken twice a day, with meals.

Common side effects include weakness, tiredness, and nausea.

Ritonavir is a prescription medicine used in combination with other medications to treat human immunodeficiency virus (HIV) infections in adults and children. Ritonavir does not cure HIV infection or AIDS.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Ritonavir may be found in some form under the following brand names:

• Norvir

• The most commonly reported side effects are: feeling weak/tired, nausea, vomiting, diarrhea, loss of appetite, abdominal pain, changes in taste, tingling feeling or numbness in hands or feet or around the lips, headache, and dizziness.
• Blood tests in patients taking ritonavir may show possible liver problems. People with liver disease such as Hepatitis B and Hepatitis C who take ritonavir may have worsening liver disease. Liver problems including rare cases of death have occurred in patients taking ritonavir. It is unclear if ritonavir caused these liver problems because some patients had other illnesses or were taking other medicines.
• Some patients taking ritonavir can develop serious problems with their pancreas (pancreatitis) which may cause death. Tell your doctor if you have nausea, vomiting, or abdominal pain. These may be signs of pancreatitis.
• Some patients have large increases in triglycerides and cholesterol. The long-term chance of getting complications such as heart attacks or stroke due to increases in triglycerides and cholesterol caused by protease inhibitors is not known at this time.
• Diabetes and high blood sugar (hyperglycemia) have occurred in patients taking protease inhibitors. Some patients had diabetes before starting protease inhibitors, others did not. Some patients need changes in their diabetes medication. Others need new diabetes medication.
• Changes in body fat have been seen in some patients taking antiretroviral therapy. These changes may include increased amount of fat in the upper back and neck ("buffalo hump"), breast and around the trunk. Loss of fat from the legs, arms and face may also happen. The cause and long term health effects of these conditions are not known at this time.
• Some patients with hemophilia have increased bleeding with protease inhibitors.
• Allergic reactions ranging from mild to severe have occurred in patients taking ritonavir.
• Changes in the electrocardiogram (EKG). Consult your physician if you experience dizziness, lightheadedness, fainting spells or abnormal heart beat. Patients with heart defects or conduction defects should avoid ritonavir.
• There have been other side effects noted in patients receiving ritonavir; however, these side effects may have been due to other medicines that patients were taking or to the illness itself. Some of these side effects can be serious. If you have questions about side effects, ask your doctor, nurse, or pharmacist. You should report any new or persistent symptoms to your doctor immediately.

Ritonavir may interact with other medicines, including those you take without a prescription. You must tell your doctor about all the medicines you are taking or are planning to take.

Do not take the following medicines with ritonavir because they can cause serious or life-threatening problems such as irregular heartbeat, breathing difficulties, or excessive sleepiness:

• Cordarone (amiodarone)
• Ergotamine, ergonovine, methylergonovine, and dihydroergotamine such as Cafergot, Migranal, D.H.E 45, and others
• Halcion (triazolam)
• Hismanal (astemizole)
• Orap (pimozide)
• Propulsid (cisapride)
• Quinidine, also known as Quinaglute, Cardioquin, Quinidex, and others
• Rythmol (propafenone)
• Seldane (terfenadine)
• Revatio (sildenafil) only when used for the treatment of pulmonary arterial hypertension
• Tambocor (flecainide)
• Uroxatral (alfuzosin hydrochloride)
• Vascor (bepridil)
• Versed (midazolam)
• Vfend (voriconazole)
• Do not take ritonavir with St. John's wort (hypericum perforatum), an herbal product sold as a dietary supplement or products containing St. John's wort. Talk with your doctor if you are taking or are planning to take St. John's wort. Taking St. John's wort may decrease ritonavir levels and lead to increased viral load and possible resistance to ritonavir or cross-resistance to other antiretroviral medicines.
• Do not take ritonavir with the cholesterol-lowering medicines Mevacor (lovastatin) or Zocor (simvastatin) because of possible serious reactions. There is also an increased risk of drug interactions between ritonavir and Lipitor (atorvastatin); talk to your doctor before you take any of these cholesterol-lowering medicines with ritonavir.

It is possible that your doctor may need to increase or decrease the dose of other medicines when you are also taking ritonavir. Remember to tell your doctor all medicines you are taking or plan to take.

The following medicines require dose reduction if taken with ritonavir:

If you are taking PDE5 inhibitors for erectile dysfunction including Viagra (sildenafil), Cialis (tadalafil), or Levitra (vardenafil), your doctor may lower your dose of these medications. You should not use sildenafil (Revatio) with ritonavir if you are being treated for pulmonary arterial hypertension. If you are taking AdcircaTM (tadalafil) for pulmonary arterial hypertension, your doctor may change your dose of this medicine.

Before you take Viagra, Cialis or Levitra with ritonavir, talk to your doctor about possible drug interactions and side effects. If you take these medications with ritonavir you may be at risk of side effects such as low blood pressure, visual changes, and penile erection lasting more than 4 hours. If an erection lasts longer than 4 hours, you should get medical help immediately to avoid permanent damage to your penis. Your doctor can explain these symptoms to you.

• If you are taking Oral contraceptives ("the pill") or the contraceptive patch to prevent pregnancy, you should use a different type of contraception since ritonavir may reduce the effectiveness of oral or patch contraceptives.
• If you are taking Mycobutin (rifabutin), your doctor will lower the dose of Mycobutin.
• If you are taking Colcrys (colchicine), your doctor will tell you what dose to use.
• If you are taking Tracleer (bosentan), your doctor will tell you what dose to use.


Other Special Considerations: 


• Ritonavir oral solution contains alcohol. Talk with your doctor if you are taking or planning to take metronidazole or disulfiram. Severe nausea and vomiting can occur.
• If you are taking both didanosine (Videx) and ritonavir: 
Didanosine and ritonavir should be separated by at least 2.5 hours.
• Rifampin, also known as Rimactane, Rifadin, Rifater, or Rifamate, may reduce blood levels of ritonavir. Be sure to tell your doctor if you are taking rifampin.
• If you are taking or before you begin using inhaled Flonase (fluticasone propionate), talk to your doctor about problems these two medicines may cause when taken together. Your doctor may choose not to keep you on inhaled Flonase.
• Rifampin and saquinavir should not be taken with ritonavir. Be sure to tell your doctor if you are taking rifampin and saquinavir.
• If you are taking or before you begin using Serevent (salmeterol) and ritonavir, talk to your doctor about problems these medicines may cause when taken together. Your doctor may choose not to keep you on Serevent (salmeterol).
• If you are taking or before you begin using Advair (salmeterol in combination with fluticasone propionate) and ritonavir, talk to your doctor about problems these two medicines may cause when taken together. Your doctor may choose not to keep you on Advair (salmeterol in combination with fluticasone propionate).

• Together with your doctor, you need to decide whether ritonavir is right for you.
• Do not take ritonavir if you are taking certain medicines. These could cause serious side effects that could cause death. Before you take ritonavir, you must tell your doctor about all the medicines you are taking or are planning to take. These include other prescription and non-prescription medicines and herbal supplements. 
• Do not take ritonavir if you have had a serious allergic reaction to ritonavir or any of its ingredients.

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of ritonavir there are no specific foods that you must exclude from your diet when receiving this medication.

Tell your doctor if:

• you are pregnant or planning to become pregnant: The effects of ritonavir on pregnant women or their unborn babies are not known.
• you are breastfeeding: Do not breastfeed if you are taking ritonavir. You should not breastfeed if you have HIV. If you are a woman who has or will have a baby, talk with your doctor about the best way to feed your baby. You should be aware that if your baby does not already have HIV, there is a chance that HIV can be transmitted through breastfeeding.
• you have liver problems: If you have liver problems or are infected with Hepatitis B or Hepatitis C, you should tell your doctor before taking ritonavir.
• you have diabetes: Some people taking protease inhibitors develop new or more serious diabetes or high blood sugar. Be sure to tell your doctor if you have diabetes or an increase in thirst and/or frequent urination.
• you have hemophilia: Some people with hemophilia have had increased bleeding. It is not known whether the protease inhibitors caused these problems. Be sure to tell your doctor if you have hemophilia types A and B.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Ritonavir falls into category B. There are no well-controlled studies that have been done in pregnant women. Ritonavir should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.

To monitor outcomes of pregnant women exposed to this medication, an Antiretroviral Pregnancy Registry has been established. Talk to your doctor about registering if you become pregnant during ritonavir therapy.

Do not breastfeed if you are taking ritonaviir. You should not breastfeed if you have HIV. If you are a woman who has or will have a baby, talk with your doctor about the best way to feed your baby. You should be aware that if your baby does not already have HIV, there is a chance that HIV can be transmitted through breastfeeding.

• You should stay under a doctor's care when taking ritonavir. Do not change your treatment or stop treatment without first talking with your doctor.
• It is very important that you take ritonavir every day exactly as your doctor prescribed it.
• The usual dose for adults is six 100 mg capsules or 7.5 mL of the oral solution twice a day (morning and night), in combination with other anti-HIV medicines.
• The dosing of ritonavir may be different for you than for other patients. Follow the directions from your doctor, exactly as written on the label.
• Children from > 1 month to 21 years of age can also take ritonavir. The child's doctor will decide the right dose based on the child's height and weight.
• Take ritonavir with food if possible.
• Ritonavir Oral Solution is peppermint/caramel flavored. You can take it alone, or may improve the taste by mixing it with 8 ounces of chocolate milk, Ensure, or Advera. ritonavir Oral Solution should be taken within 1 hour if mixed with these items. Ask your doctor, nurse or pharmacist about other ways to improve the taste of ritonavir Oral Solution.
• Do not change or stop taking ritonavir without first talking with your health care provider.
• When your ritonavir supply starts to run low, get more from your doctor or pharmacy. This is very important because the amount of virus in your blood may increase if the medicine is stopped for even a short time. The virus may develop resistance to ritonavir and become harder to treat.
• Be sure to set up a schedule and follow it carefully.
• Only take medicine that has been prescribed specifically for you. Do not give ritonavir to others or take medicine prescribed for someone else.

Take ritonavir exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. Your doctor will determine the best dose for you.

• Dose modification for ritonavir is necessary when used with other protease inhibitors.
• Adult patients: 600 mg twice-daily with meals if possible.
• Pediatrics patients: The recommended twice daily dose for children greater than one month of age is based on body surface area and should not exceed 600 mg twice daily with meals if possible.

If you think that you took more than the prescribed dose of this medicine, contact your local poison control center or emergency room immediately.

As with all prescription medicines, ritonavir should be kept out of the reach of young children. ritonavir liquid contains a large amount of alcohol. If a toddler or young child accidentally drinks more than the recommended dose of ritonavir, it could make him/her sick from too much alcohol. Contact your local poison control center or emergency room immediately if this happens.

• Keep ritonavir and all other medicines out of the reach of children.
• Store ritonavir tablets and ritonavir oral solution at room temperature.
• Do not refrigerate ritonavir oral solution. Avoid exposing ritonavir oral solution to excessive heat or cold.
• Refrigeration of ritonavir soft gelatin capsules by the patient is recommended, but not required if used within 30 days and stored below 77°F (25°C). Avoid exposing ritonavir soft gelatin capsules to excessive heat or cold.
• Store ritonavir soft gelatin capsules and ritonavir oral solution in the original container.
• Shake ritonavir oral solution well before each use.
• Use ritonavir soft gelatin capsules, tablets, and ritonavir oral solution by the expiration date on the bottle.

WARNING: DRUG-DRUG INTERACTIONS LEADING TO POTENTIALLY SERIOUS AND/OR LIFE THREATENING REACTIONS

Co-administration of ritonavir with several classes of drugs including sedative hypnotics, antiarrhythmics, or ergot alkaloid preparations may result in potentially serious and/or life-threatening adverse events due to possible effects of ritonavir on the hepatic metabolism of certain drugs. Review medications taken by patients prior to prescribing ritonavir or when prescribing other medications to patients already taking ritonavir.