Nelfinavir (By mouth)


Nelfinavir (nel-FIN-a-vir)

Treats human immunodeficiency virus (HIV) infection. HIV causes acquired immune deficiency syndrome (AIDS). Nelfinavir does not cure HIV or AIDS, but may help slow the progress of the disease.

Brand Name(s)


There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to nelfinavir. You should not use this medicine if you use certain heart rhythm medicines (such as amiodarone, quinidine, Cardioquin®, Cordarone®, Quinaglute®, or Quinidex®), alfuzosin (Uroxatral®), cisapride (Propulsid®), lovastatin (Mevacor®), oral midazolam (Versed®), pimozide (Orap®), rifampin (Rifadin®, Rimactane®), sildenafil (Revatio®), simvastatin (Zocor®), St John's wort, triazolam (Halcion®), or ergot medicines (such as dihydroergotamine, ergonovine, ergotamine, methylergonovine, DHE 45®, Ergomar®, Ergotrate®, or Methergine®). Do not use this medicine if you have moderate or severe liver disease.

How to Use This Medicine

Powder, Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.Do not change the dose or stop using this medicine without asking your doctor first.
  • If you also use didanosine (Videx®), take it 1 hour before or at least 2 hours after you take nelfinavir.
  • It is best to take this medicine with food or milk.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
  • If you cannot swallow the tablet whole, you may dissolve it in a small amount of water. Be sure to drink or swallow the entire mixture right away. Then refill your glass with water and drink it so that none of the medicine is left in the glass.
  • Measure the oral powder carefully using the measuring scoop provided with the medicine. Mix the powder with a small amount of water, milk, soy milk, baby formula, or a dietary supplement drink. Do not use apple juice, grapefruit juice, orange juice, or applesauce. After you mix the medicine with a liquid, take the mixture right away. Be sure to drink or swallow all of the mixture. If you cannot use the mixture right away, you may store it in the refrigerator for up to 6 hours.
  • Nelfinavir is used with other medicines to treat HIV infection. Be sure to take all of the medicines your doctor ordered and to take them at the right times.
  • This medicine works best if there is a constant amount in the blood. To keep blood levels constant, take this medicine at the same time each day and do not miss any doses. Contact your doctor or pharmacist when your supply of this medicine runs low. Do not allow yourself to run out of this medicine.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you use other medicines to treat HIV or AIDS (such as delavirdine, didanosine, indinavir, nevirapine, ritonavir, saquinavir, Crixivan®, Fortovase®, Invirase®, Norvir®, Rescriptor®, or Videx®), medicine to treat an infection (such as azithromycin, rifabutin, Mycobutin®, or Zithromax®), stomach medicine (such omeprazole or Prilosec®), medicine to lower cholesterol (such as atorvastatin, fluvastatin, pravastatin, rosuvastatin, Crestor®, Lescol®, Lipitor®, or Pravachol®), bosentan (Tracleer®), colchicine (Colcrys®), salmeterol (Serevent®), or birth control pills that contain estrogen (such as Loestrin®, Ortho-Novum®, or Ovcon®).
  • Tell your doctor if you also use medicine to treat seizures (such as carbamazepine, phenobarbital, phenytoin, Dilantin®, or Tegretol®), medicine to treat problems with erection (such as sildenafil, tadalafil, vardenafil, Adcirca?, Cialis®, Levitra®, or Viagra®), medicine that weakens your immune system (such as cyclosporine, sirolimus, tacrolimus, Gengraf®, Neoral®, Protopic®, Rapamune®, or Sandimmune®), pain medicine (such as methadone or Dolophine®), inhaled steroid medicine (such as fluticasone or Flonase®), medicine to treat depression (such as trazodone or Desyrel®), or a blood thinner (such as warfarin or Coumadin®).

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or if you have liver disease, diabetes, autoimmune disorders (such as Graves disease, polymyositis, or a history of Guillain-Barré syndrome), or hemophilia.
  • You should not breastfeed if you have HIV or AIDS, because you might give the infection to your baby through your breast milk.
  • This medicine will not keep you from giving HIV to your partner during sex. Make sure you understand and practice safe sex, even if your partner also has HIV. Do not share needles with anyone.
  • Birth control pills may not work as well while you are using this medicine. To avoid pregnancy, use another form of birth control together with your pills.
  • Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia, herpes, or tuberculosis.
  • This medicine may increase blood sugar levels. Tell your doctor if you have increased hunger or thirst, changes in how much you urinate, or unusual weight loss. Check with your doctor if you notice a change in the results of your blood or urine sugar tests.
  • The oral powder contains phenylalanine. Tell your doctor if you have phenylketonuria (PKU).
  • This medicine may cause you to have changes in body fat. Tell your doctor if you notice an increased amount of fat in your upper back and neck or around the chest and stomach area. You might also lose fat from the legs, arms, and face.
  • Your doctor will need to check your blood at regular visits while you are using this medicine. Be sure to keep all appointments.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Bloody or black, tarry stools
  • Change in how much or how often you urinate
  • Fever, chills, cough, sore throat, and body aches
  • Increased thirst or hunger, or unusual weight loss
  • Unusual bleeding, bruising, or weakness
  • Yellow skin or eyes

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea, nausea, or stomach pain
  • Weight gain around your neck, upper back, breast, or waist

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

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This page was last updated: September 18, 2013

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