Viracept (Nelfinavir) for HIV

Viracept (nelfinavir) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat human immunodeficiency virus type 1 (HIV-1) infection in adults and children ages 2 and older.

How Viracept Works and How It’s Taken

Viracept is a type of HIV medicine called a protease inhibitor. It blocks HIV-1 protease, an enzyme the virus needs to make new virus particles that can infect other cells.

Doctors prescribe Viracept when treating HIV-1 in adults and children ages 2 and older, in combination with other antiretroviral medicines.

HIV-1 is the virus that causes acquired immune deficiency syndrome (AIDS).

Viracept comes as tablets and an oral powder. It should be taken with a meal.

If you or your child cannot swallow Viracept tablets, the tablets may be dissolved in a small amount of water. Mix the cloudy liquid well and drink it right away. Rinse the glass with water and drink the rinse to make sure the full dose is taken.

Viracept oral powder may be mixed with a small amount of water, milk, formula, soy formula, soy milk, or a dietary supplement. The entire mixture should be taken to make sure the full dose is received. If the mixture is not taken right away, it should be refrigerated and used within six hours.

Do not mix Viracept oral powder with acidic foods or juices, such as orange juice, apple juice, or applesauce, because the mixture may taste bitter. Do not mix the powder with water in its original container.

Typical Dosing for HIV

For adults and adolescents ages 13 and older, the recommended dose is either:

1,250 milligrams twice daily — Five 250-milligram tablets or two 625-milligram tablets per dose
750 milligrams three times daily — Three 250-milligram tablets per dose

For children ages 2 to 12, the dose is based on body weight. The healthcare provider will choose the right dose and form of Viracept.

For twice-daily dosing, the recommended amount is 45 to 55 milligrams per kilogram per dose:

10 to 12 kilograms — Two 250-milligram tablets per dose
13 to 18 kilograms — Three 250-milligram tablets per dose
19 to 20 kilograms — Four 250-milligram tablets per dose
21 kilograms or more — Four to five 250-milligram tablets per dose

For dosing three times daily, the recommended amount is 25 to 35 milligrams per kilogram per dose:

10 to 12 kilograms — One 250-milligram tablet per dose
13 to 20 kilograms — Two 250-milligram tablets per dose
21 kilograms or more — Three 250-milligram tablets per dose

Children may take 250-milligram tablets or Viracept oral powder. The healthcare provider should tell the caregiver exactly how much powder to give based on the child’s weight.

This information is based on prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Viracept Side Effects

In clinical studies of Viracept, the following side effects occurred in about 1 percent to 20 percent of adults and adolescents, depending on the study and treatment group.

Common side effects in adults and adolescents include:

Diarrhea
Nausea
Flatulence (gas)
Rash

Common side effects in children include:

Diarrhea
Rash
Anorexia (loss of appetite)
Stomach pain
Leukopenia or neutropenia (low white blood cell counts)

Serious Side Effects and Warnings

Viracept can cause serious side effects that may require immediate medical attention. These include:

High blood sugar or diabetes — New or worsening diabetes or high blood sugar levels can occur.
Increased bleeding in people with hemophilia — Bleeding can occur, including into joints or under the skin.
Changes in body fat — Fat can build up or be lost in different parts of the body.
Immune reconstitution syndrome — As the immune system starts fighting infections, it can trigger inflammation. Autoimmune conditions have also been reported.
Hypersensitivity (severe allergic reactions) — Reactions can include bronchospasm, fever, swelling, or moderate to severe rash.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Viracept

Before starting Viracept, tell your doctor if you have any allergies to nelfinavir or any ingredients in Viracept.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Also tell your doctor if you:

Have liver problems
Have kidney problems
Have phenylketonuria (Viracept oral powder contains aspartame)
Have diabetes or high blood sugar
Have hemophilia

Do not take Viracept with:

Alfuzosin
Amiodarone or quinidine
Rifampin
Lurasidone or pimozide
Ergot medicines, including dihydroergotamine, ergotamine, or methylergonovine
Cisapride
St. John’s wort
Lovastatin or simvastatin
Sildenafil (Revatio) when used for pulmonary arterial hypertension
Triazolam
Midazolam taken by mouth

Do not miss doses or let your supply of Viracept run out. The amount of virus in your blood may increase, and the virus may become harder to treat.

If you miss a dose, take it as soon as possible and then return to your regular schedule. If you skip a dose, do not take two doses at the same time.

If you are pregnant or become pregnant while taking Viracept, tell your healthcare provider. Because liver-related problems have been reported during pregnancy and Viracept levels may be lower later in pregnancy, your healthcare provider may consider another HIV medicine.

A pregnancy registry tracks pregnancy outcomes in people exposed to Viracept. Healthcare providers can register pregnancies through the Antiretroviral Pregnancy Registry or by calling 800-258-4263.

Viracept may make some estrogen-based birth control pills less effective. Use an alternative or additional form of birth control as advised by your healthcare provider.

Do not breastfeed while taking Viracept. HIV-1 can pass to a baby through breast milk, and nelfinavir can also pass into breast milk.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Viracept for HIV?

Viracept was studied as part of combination HIV treatment.

In one adult study, 61 percent of people taking Viracept 1,250 milligrams twice daily with stavudine and lamivudine had HIV RNA below 400 copies per milliliter at week 48. This was compared with 58 percent of people taking Viracept 750 milligrams three times daily with the same two medicines.

In a study of treatment-experienced children, 42 percent of children taking stavudine, lamivudine, and Viracept had HIV RNA below 400 copies per milliliter at week 48.

Can Viracept be used with other medicines for HIV?

Yes. Viracept is meant to be used with other HIV medicines, called antiretroviral medicines, to treat HIV-1 infection. Your healthcare provider will choose the combination that is right for you.

Can Viracept interact with other HIV medicines?

Yes. Viracept can interact with some HIV medicines:

Delavirdine — Viracept levels may increase, and delavirdine levels may decrease.
Nevirapine — Viracept levels may decrease.
Didanosine — Take didanosine one hour before or two hours after Viracept.
Indinavir — Levels of both medicines may increase.
Ritonavir — Viracept levels may increase.
Saquinavir — Levels of both medicines may increase.

For several of these combinations, safe and effective doses have not been established. Tell your healthcare provider about all HIV medicines you take so they can check for interactions.