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|Ritonavir Ritonavir

Ritonavir

Generic name: Ritonavir
Brand names: Norvir

Why is Ritonavir prescribed?

Ritonavir is prescribed to slow the progress of HIV (human immunodeficiency virus) infection. HIV causes the immune system to break down so that it can no longer respond effectively to infection, leading to the fatal disease known as acquired immune deficiency syndrome (AIDS). Without treatment, HIV takes over certain human cells, especially white blood cells, and uses the inner workings of the infected cell to make additional copies of itself. Ritonavir belongs to a class of HIV drugs called protease inhibitors, which work by interfering with an important step in this process. Although Ritonavir cannot get rid of HIV already present in the body, it can reduce the amount of virus available to infect other cells.

Ritonavir is used in combination with other HIV drugs called nucleoside analogues (Retrovir, Hivid, and others). These two types of drugs act against HIV in different ways thus improving the odds of success.

Most important fact about Ritonavir

Do not take Ritonavir with the following medications. The combination could cause serious, even life-threatening, effects.

Amiodarone (Cordarone)
Astemizole
Bepridil (Vascor)
Dihydroergotamine (D.H.E.)
Ergonovine
Ergotamine (Wigraine)
Flecainide (Tambocor)
Methylergonovine (Methergine)
Midazolam (Versed)
Pimozide (Orap)
Propafenone (Rythmol)
Quinidine (Quinidex)
Terfenadine
Triazolam (Halcion)

Be sure to tell your doctor and pharmacist what medications you are taking, both prescription and over-the-counter, and let them know when you stop taking any medication.

How should you take Ritonavir?

Take Ritonavir every day, exactly as prescribed by your doctor. Do not share Ritonavir with anyone and do not take more than your recommended dosage.

Take Ritonavir with food, if possible, or the medication may not work properly.

Ritonavir is available in soft gelatin capsule and oral solution forms. If you are taking Ritonavir oral solution and want to improve the taste, you can mix the liquid with chocolate milk or a liquid nutritional product (Ensure or Advera) within 1 hour of taking the dose. Use a measuring cup or spoon to measure each dose of the oral solution accurately. A household teaspoon may not hold the correct amount of oral solution.

--If you miss a dose...

Take it as soon as possible. If it is almost time for the next dose, skip the one you missed and go back to your regular schedule. Never double the dose.

--Storage instructions...

Capsules are best kept in the refrigerator, although they do not require refrigeration if used within 30 days and stored below 77°F. Protect from light and heat.

Do not refrigerate the oral solution. Store at room temperature. Shake before each use. Avoid exposure to extreme heat and keep cap tightly closed.

Keep Ritonavir in its original container and use by the expiration date.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Ritonavir.

• More common side effects may include:
  Abdominal pain, anxiety, bedwetting, confusion, diarrhea, dizziness, drowsiness, fatigue, fever, general feeling of illness, headache, indigestion, insomnia, loss of appetite, muscle aches, nausea, numbness or tingling sensation around the face or mouth, "pins and needles" sensation in the arms and legs, rash, sore or irritated throat, sweating, taste alteration, vomiting, weakness

Why should Ritonavir not be prescribed?

If you have ever had an allergic reaction to Ritonavir or any of its ingredients, do not take the drug. Never combine Ritonavir with the drugs listed under "Most important fact about Ritonavir."

Special warnings about Ritonavir

Ritonavir has been studied for only a limited period of time. Its long-term effects are still unknown.

Ritonavir is not a cure for AIDS or HIV infection. You may continue to experience symptoms and develop complications, including opportunistic infections (rare diseases that attack when the immune system falters, such as certain types of pneumonia, tuberculosis, and fungal infections).

Ritonavir does not reduce the danger of transmission of HIV to others through sexual contact or blood contamination. Therefore, you should continue to avoid practices that could give HIV to others.

If you have liver disease, take Ritonavir with caution; it has caused liver damage in some patients. It has also been known to trigger or aggravate cases of diabetes. It may increase your cholesterol levels. And it can also cause a serious problem called pancreatitis. If you develop warning signs such as nausea, vomiting, and abdominal pain, be sure to tell your doctor. You may have to stop taking the drug.

Some patients undergo an accumulation or redistribution of body fat while taking Ritonavir. It"s not known whether this has any ill-effects on health over the long term.

Possible food and drug interactions when taking Ritonavir

Combining Ritonavir with certain drugs (see "Most important fact about Ritonavir") may cause serious or life-threatening effects. Other drugs may cause less dangerous--but still worrisome--effects. It is especially important to check with your doctor before combining Ritonavir with the following:

Anticonvulsants such as Depakote, Dilantin, Klonopin, Lamictal, Tegretol, and Zarontin
Antidepressants such as Norpramin, Prozac, Serzone, and Wellbutrin
Anti-nausea drugs such as Marinol
Atovaquone (Mepron)
Calcium channel blockers (another type of heart and blood pressure medications) such as Calan, Cardizem, and Procardia
Cholesterol-lowering drugs such as Lipitor, Mevacor, and Zocor
Clarithromycin (Biaxin)
Didanosine (Videx)
Disulfiram (Antabuse)
Heart medications such as lidocaine, Mexitil, and Norpace
Immunosuppressants such as Neoral, ProGraf, Rapamune, and Sandimmune
Indinavir (Crixivan)
Itraconazole (Sporanox)
Ketoconazole (Nizoral)
Medications for mental illness such as Mellaril, Risperdal, and Trilafon
Methadone
Methamphetamine
Metoprolol (Lopressor)
Metronidazole (Flagyl)
Oral contraceptives
Pain-killers such as Demerol, Darvon, and Ultram
Quinine
Rifabutin (Mycobutin)
Rifampin (Rifadin)
St. John"s wort (hypericum perforatum)
Saquinavir (Invirase)
Sedatives such as Ambien, Dalmane, ProSom, Tranxene, and Valium
Sildenafil (Viagra)
Steroids such as dexamethasone, fluticasone, and prednisone
Timolol (Timoptic)
Theophylline (Theo-Dur)

Less significant interactions may occur with many other drugs. Your wisest course is to check with your doctor before combining any drug with Ritonavir.

Tobacco use decreases the effects of Ritonavir. The effects of antacids taken with Ritonavir have not been studied.

Special information if you are pregnant or breastfeeding

The effects of Ritonavir during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, tell your doctor immediately.

To avoid transmitting HIV to a newborn baby, HIV-positive women should not breastfeed.

Recommended dosage

ADULTS

The recommended dose of Ritonavir is 600 milligrams twice a day with food.

Should you experience nausea when first starting on Ritonavir, your doctor may lower your starting dosage to 300 milligrams twice a day for 1 day, 400 milligrams twice a day for 2 days, 500 milligrams twice a day for 1 day, and then 600 milligrams twice a day thereafter.

Your doctor may suggest taking Ritonavir alone at first and adding a second drug later in the first 2 weeks of therapy. This approach may cause fewer stomach problems.

If you are taking Ritonavir along with saquinavir, the dosage of both drugs may be reduced to 400 milligrams twice daily.

CHILDREN AGE 2 TO 16 YEARS

The dosage of Ritonavir in children is based on the child"s size, and should not exceed 600 milligrams twice a day. Use of a special spoon or dosing syringe with measurements on it will help ensure that the child receives the proper dose.

Overdosage

Information on acute overdose with Ritonavir is limited. However, any medication taken in excess can have serious consequences. If you suspect an overdose, seek emergency medical treatment immediately.

• Symptoms of Ritonavir overdose may include:
  Numbness, tingling, or a "pins and needles" sensation, particularly in the arms and legs

Because Ritonavir oral solution is 43 percent alcohol, severe alcohol toxicity can follow its ingestion by a young child.