Ritonavir

Other Names: RTV, Norvir^®

Manufacturer: Abbott Laboratories

What is it?

Ritonavir belongs to a group of drugs known as protease inhibitors. It is used to treat HIV, a retrovirus. Retroviruses use the genetic material in the body’s cells to produce more virus which can infect other cells.

How does it work?

Ritonavir interferes with the life cycle of HIV to stop it from producing more virus. Specifically, ritonavir ties up the protease enzyme, which slows the production of new virus to prevent other cells from becoming infected.

How do I take it?

· Ritonavir is available as 100 mg capsules and as an oral solution (80mg/ml).

· The dose varies depending upon what other medications are used in combination with ritonavir.

· Ritonavir should be taken with food to increase absorption of the medication into the bloodstream.

It is extremely important that you take ritonavir and your other antiretroviral medications exactly as directed. You should set up a system that will help you remember to take your medicines so that you do not miss any doses. If you miss a dose, take it as soon as possible; however, if you skip a dose, do not take two doses at once. Do not stop taking the medication for any reason at any time unless you are directed to do so by your study clinician. If you are unable to continue taking your medication due to side effects, you should contact your study clinician immediately.

Special Considerations

· The bottle containing your ritonavir capsules should be stored in the refrigerator. You may keep several doses of ritonavir out of the refrigerator if kept at room temperature (less than 77° F).

· Ritonavir oral solution should be stored at room temperature and shaken well before measuring each dose.

Please bring your medication bottles (empty and partially used) to each study visit.

Interactions

Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. Ritonavir has a number of serious drug interactions. You need to be familiar with the names of medications that you are taking and compare them to the medications listed below. Make sure that everyone who is prescribing or dispensing medications to you knows that you are taking ritonavir.

Ritonavir should not be taken with any of the following medicaitons:

astemizole (Hismanal^®)
triazolam (Halcion^®)
ergotamine
terfenadine (Seldane^®)
cisapride (Propulsid^®)
dihydroergotamine
midazolam (Versed^®)
pimozide (Orap^®)

Inform your study clinician if you are taking any of the following medications:

· antidepressant medications

· oral contraceptives

· cancer chemotherapy agents

· clarithromycin (Biaxin^®)

· theophylline

· neuroleptics/tranquilizers

· warfarin (Coumadin^®)

· mexiletine

· blood pressure medications

· anticonvulsants (phenobarbital, phenytoin, carbamazepine)

Side Effects

Not everyone experiences side effects. When they do occur, they may be mild, moderate or severe. Some side effects cannot be felt by the patient but can be found through laboratory tests, so it is important to see your study clinician regularly for checkups so that side effects can be detected early and treated.

The most common side effects of ritonavir are nausea, vomiting, diarrhea, abdominal pain, weight loss, taste disturbances, circumoral paresthesia (numb sensation around the mouth), weakness or loss of strength.

Increases in blood sugar or the development of diabetes has been reported in a small number of patients taking protease inhibitors. Symptoms include increased thirst or hunger, weight loss, increased need to urinate, fatigue, or dry, itchy skin. Please contact your study clinician if any of these side effects occur.

Also, a condition called lipodystrophy (abnormal use of fats in the body) has been reported in patients taking protease inhibitors. Symptoms vary among individuals, but they may include accumulation of fat tissue in the stomach area or the upper back, and a loss of mass in other areas of the body. Some people have experienced increases in cholesterol and triglycerides that have required the use of lipid lowering medications.

Last Updated: 7/15/99