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Other drug names: A-Am An-Az B C-Ch Ci-Cz D-Dh Di-Dz E F G H I-J K-L M-Mh Mi-Mz N-Nh Ni-Nz O P-Pl Pm-Pz Q-R S-Sn So-Sz T-To Tp-Tz U-V W-Z 0-9   

Nelfinavir (Systemic)

Brand Names

In the U.S.-

  • Viracept


  • Antiviral, systemic


Nelfinavir ( nel-FIN-a-veer) is used, usually in combination with other medicines, in the treatment of the infection caused by the human immunodeficiency virus (HIV). HIV is the virus that causes acquired immune deficiency syndrome (AIDS).

Nelfinavir will not cure or prevent HIV infection or AIDS; however, it helps keep HIV from reproducing and appears to slow down the destruction of the immune system. This may help delay the development of problems usually related to AIDS or HIV disease. Nelfinavir will not keep you from spreading HIV to other people. People who receive this medicine may continue to have other problems usually related to AIDS or HIV disease.

This medicine is available only with your doctor's prescription, in the following dosage forms:

  • Oral powder (U.S.)
  • Tablets (U.S.)

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For nelfinavir, the following should be considered:

Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to nelfinavir. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy- Studies have not been done in humans. However, nelfinavir has not been reported to cause birth defects or other problems in animal studies.

Breast-feeding- It is not known whether nelfinavir passes into breast milk. However, breast-feeding is usually not recommended in AIDS patients because of the risk of passing the AIDS virus on to the nursing infant.

Children- This medicine has been tested in children between 2 and 13 years of age and, in effective doses, has not been reported to cause different side effects or problems in children than it does in adults.

Older adults- Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. There is no specific information comparing use of nelfinavir in the elderly with use in other age groups.

Other medicines- Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking nelfinavir, it is especially important that your health care professional know if you are taking any of the following:

  • Amiodarone (e.g., Cordarone) or
  • Astemizole (e.g., Hismanal) or
  • Cisapride (e.g., Propulsid) or
  • Ergot medicines (dihydroergotamine [e.g., D.H.E. 45], ergoloid mesylates [e.g., Hydergine], ergonovine [e.g., Ergotrate], methylergonovine [e.g., Methergine], methysergide [e.g., Sansert]) or
  • Midazolam (e.g., Versed) or
  • Quinidine (e.g., Quinidex) or
  • Terfenadine (e.g., Seldane) or
  • Triazolam (e.g., Halcion)-There is a possibility that nelfinavir may interfere with the removal of these medicines from the body, which could lead to serious side effects
  • Oral contraceptives (birth control pills)-Nelfinavir may cause these medicines to be less effective
  • Rifabutin (e.g., Mycobutin)-Use of this medicine with nelfinavir may increase the amount of rifabutin and decrease the amount of nelfinavir in the body
  • Rifampin (e.g., Rifadin)-Use of this medicine with nelfinavir may decrease the amount of nelfinavir in the body

Other medical problems- The presence of other medical problems may affect the use of nelfinavir. Make sure you tell your doctor if you have any other medical problems, especially:
  • Liver disease-Effects of nelfinavir may be increased because of slower removal from the body
  • Phenylketonuria (a metabolic problem)-The oral powder form of nelfinavir contains phenylalanine, which may not be broken down properly in people with this condition

Proper Use of This Medicine

Nelfinavir works best if it is taken with food.

Take this medicine exactly as directed by your doctor. Do not take it more often, and do not take it for a longer time than your doctor ordered. Also, do not stop taking this medicine without checking with your doctor first.

Keep taking nelfinavir for the full time of treatment, even if you begin to feel better.

This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times, day and night. For example, if you are to take three doses a day, the doses should be spaced about 8 hours apart. If you need help in planning the best times to take your medicine, check with your health care professional.

Only take medicine that your doctor has prescribed specially for you. Do not share your medicine with others.


The dose of nelfinavir will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of nelfinavir. If your dose is different, do not change it unless your doctor tells you to do so.

  • For oral dosage form (oral powder):
    • For treatment of HIV infection:
      • Children 2 to 13 years of age-Dose is based on body weight and must be determined by your doctor. The usual dose is 20 to 30 milligrams (mg) per kilogram (kg) (9 to 13.6 mg per pound) of body weight three times a day with food.
      • Children less than 2 years of age-Use and dose must be determined by your doctor.
  • For oral dosage form (tablets):
    • For treatment of HIV infection:
      • Adults and teenagers-750 mg three times a day with food.
      • Children 2 to 13 years of age-Dose is based on body weight and must be determined by your doctor. The usual dose is 20 to 30 mg per kg (9 to 13.6 mg per pound) of body weight three times a day with food.
      • Children less than 2 years of age-Use and dose must be determined by your doctor.

Missed dose-

If you miss a dose of this medicine, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

Do not take any other medicines without checking with your doctor first . To do so may increase the chance of side effects from nelfinavir.

Nelfinavir should be taken at least 2 hours before or 1 hour after taking didanosine.

This medicine may decrease the effects of some oral contraceptives (birth control pills). To avoid unwanted pregnancy, it is a good idea to use some additional contraceptive measures while being treated with nelfinavir .

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly and check for unwanted effects, especially increases in blood sugar.

Side Effects of This Medicine

Side Effects of This Medicine

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • Confusion;  dehydration;  dry or itchy skin;  fatigue;  fruity mouth odor;  increased hunger;  increased thirst;  increased urination;  nausea;  vomiting;  weight loss 

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

  • More common
    • Diarrhea 

  • Less common
    • Intestinal gas;  skin rash 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT