What is Norvir?
Norvir is a drug that is used in antiretroviral therapy (ART). It is produced by “AbbVie” company. Norvir is a protease inhibitor. The drug blocks the enzyme protease. HIV protease acts like a chemical scissors. It cuts the raw material for HIV into specific pieces that are needed to build new virus. Protease inhibitors “inhibit” the operation of these scissors.
WHO SHOULD TAKE IT?
Norvir was approved in 1996 as an antiretroviral drug for people with HIV. It was studied for reception by adults and children older than 1 month.
There are no absolute rules about when to start ART. You and your doctor should take into account CD4 cell count, viral load, any manifesting symptoms that you have, and your attitude to start ART. The fact sheet 404 has more information about the leadership ART.
If you take Norvir with other ARVs, viral load can drop to a very low level, and the number of CD4 increases. This should mean staying healthier longer.
Norvir slows down the liver, which can lead to increased levels of certain drugs, including protease inhibitors. This can cause some dangerous interactions with other drugs.
Norvir is rarely used as a protease inhibitor. It is quite difficult for patients to tolerate. However, it is quite often used to boost levels of other protease inhibitors in the blood. The dosage to enhance the action of protease inhibitors is much lower than the total dose for the HIV response that helps to minimize side effects.
Many new copies of HIV are mutations. They are a little different from the original virus. Some mutations can keep multiplying even when you are taking ARVs. If this happens, the drug ceases to act. This condition is called “developing resistance” to the drug. Look at the fact sheet 126 for more information on resistance.
Sometimes, if your virus develops resistance to one drug, it will also have resistance to other ARVs. This is called “cross-resistance”.
Resistance can develop very quickly, so it’s important to take ARVs according to instructions, on schedule, and not to skip or reduce doses.
HOW IS IT TAKEN?
Norvir is taken orally in form solution or capsule. A full dose (when Norvir is the only protease inhibitor) is 600 milligrams twice a day. But more Norvir is almost never used in such dosages. Norvir was approved for use to children older than 1 month at a dose of 350 mg to 450 mg per square meter of body area.
Norvir is primarily used to boost levels of other protease inhibitors in the blood. It is usually taken 1 or 2 capsules of 100 mg at each dose. Make sure you know what dose of Norvir was prescribed for you, when and how to take the drug.
A small amount of Norvir is included in Kaletra capsules as the amplifier. Kaletra is also produced by “AbbVie” company.
In 1998 it developed a liquid form of Norvir. Many people believe that the liquid form tastes bad. However, some people find the liquid more convenient, especially for children. Liquid form of the drug should not be frozen. Shake the bottle before taking the drug.
A pharmacist must keep new soft gel Norvir capsules in the refrigerator. You should keep Norvir in your refrigerator, but it can also be stored at room temperature (below 25 degrees C) for up to 30 days.
If you use a full dosage of Norvir, it gradually increases in the first few days to reduce side effects.
WHAT ARE THE POSSIBLE SIDE EFFECTS?
The most common side effects are nausea, vomiting, gas and diarrhea. Some patients also experience tingling or numbness around the lips, strange taste when eating food. In clinical trials about one third of patients had to stop taking Norvir because of side effects. However, in case of the lower “booster” doses of Norvir, side effects appear more rarely.
For many people, the side effects of Norvir last only from 2 to 4 weeks. If they remained after 4 weeks, in most cases they were permanent.
HOW DOES IT REACT WITH OTHER DRUGS?
Norvir can interact with other drugs or supplements that you take. These interactions can change the amount of drug in your bloodstream and cause an underdose – or overdose. The influence of drugs on each other is continuously identified.
Drugs, which you must be careful with, include other ARVs, drugs to treat tuberculosis (look at fact sheet 518), disorders of erection (such as Viagra), for heart rhythm.