Nelfinavir (Oral)

As a protein inhibitor, Nelfinavir prevents the multiplication of the human immunodeficiency virus (HIV) in the body. It could also lessen the amount of HIV in the body.


Nelfinavir is a synthetic antiviral agent that is used for treatment by individuals infected with the human immunodeficiency virus (HIV). It is also referred to as Viracept which is its brand name. It is normally administered orally by taking the tablet or reconstituting a solution of the oral powder. Doctors usually prescribe it in combination with other antiretroviral drugs in HIV treatment.

Nelfinavir belongs to a group of drugs known as Protease Inhibitors. Protein inhibitors are a class of antiviral medications broadly used in the treatment of hepatitis C and HIV/AIDS. PIs inhibit viral replication through selectively binding on the viral proteases, in this case HIV_1 protease, and block the protein precursors which are needed in production of the transmittable viral particles.

Once one is infected with HIV, the virus replicates itself fast inside the cells of the body. From the cells, the viruses spread rapidly all through the body infecting other body cells. In this way, the HIV infection carries on even amongst new cells which are frequently being produced in the body. Nelfinavir, as a protein inhibitor, therefore works by blocking the activity of the HIV-1 protease enzyme.

Protease is the enzyme that facilitates the structural formation of proteins that form the body of the virus. Defective viruses (immature and non-infectious) that are incapable of infecting other body cells are hence formed as a result of the protease activity being inhibited. This leads to the reduction in the number of viruses in the body, decreasing the viral load. Nelfinavir has activity against both HIV 1 and 2.

Nelfinavir is normally used together with other antiviral medications to treat HIV/AIDS. Although HIV/AIDS has no cure, it can be managed by consistent use of antiretroviral drugs like nelfinavir which lower the viral load. It is essential because it enables people infected with the virus to stay healthy and live longer. People living with HIV/AIDS should take precautionary measures like avoiding sharing personal effects (razors, toothbrushes, needles) or unprotected sexual contact with uninfected individuals to prevent the spread of the virus.

Conditions Treated

  • HIV infection
  • AIDS

Type Of Medicine

  • Protease inhibitor

Side Effects

Any drug has a purpose for which it was intended for or an expected result/effect. However, most drugs have side effects which are the detrimental and unwanted effects produced accompanying the intended ones. These side effects may occur in isolation, others simultaneously and others do not occur at all depending on the body response of the patient. There are frequently occurring side effects, and there are rare ones. One does not have to experience all the side effects accompanying treatment.

Nelfinavir may cause severe side effects like liver failure for individuals with moderate to extreme liver impairment. The most common side effect of Nelfinavir is diarrhea or loose stool. Your doctor could give you anti-diarrhea medicine to lessen this side effect and you should also stay hydrated. This drug may occasionally cause a rise in the blood sugar level leading to hyperglycemia or diabetes. Using nelfinavir may also cause immune reconstitution syndrome (IRIS), which is an inflammatory response to infection mainly occurring in patients whose nelfinavir treatment is accompanied by other HIV drugs.

Report to your medical provider immediately if you have any serious side effect like joint pains, persistent muscle aches, body weakness, extreme tiredness/fatigue, tingling or numbness of the arms, legs, feet or hands or constant headaches. Furthermore, look out for signs of an infection such as fever, chills, and coughs, flu symptoms or persistent sores in the mouth. You may also experience symptoms of an enlarged thyroid like irritability, irregular or fast heartbeat, protruding eyes, unusual swelling of the neck or thyroid (goiter). Other common side effects could be difficulty in swallowing, difficulty in breathing or problematic and uncontrolled movement of the eyes, paralysis, difficulty in speech or slurred speech or a drooping face. Using nelfinavir may also have an effect of changes in body fat (redistribution/accumulation) which could be either increased fat in the mid-section or reduced fat in the limbs.

Other serious side effects include:

  • Hypersensitivity reactions with signs such as red, itching, swollen, blistered or peeling skin sometimes accompanied by fever, hives, skin rash, wheezing, voice hoarseness, tightness in the throat or chest, and bloating of the face, throat, lips or tongue.
  • Symptoms of high blood sugar like frequent passing of urine, increased thirst, increased hunger, flushing, fruity breath odour, fast breathing, blurry vision or weight loss.
  • Persistent nausea
  • Flatulence or stomach gas
  • Increased bleeding in people with hemophilia
  • Jaundice (yellowing of the skin and eyes)
  • Failure of the pancreas (pancreatitis)

Below is a list of the rare or less frequent side effects:

  • Sores in the mouth, nose, eyes or throat
  • Confusion
  • Dehydration
  • Vomiting/ throwing up
  • Unusual fatigue or general body weakness
  • Dry, pale or itchy skin, feeling light-headed/dizziness/drowsiness, trouble breathing or shortness of breath, trouble concentrating
  • Abdominal or stomach pain
  • Clay-colored stool
  • Lack of appetite
  • Easy bruising and unusual bleeding in the mouth, nose, or rectum, red or purple spots under the skin
  • Irritability, rapid/ irregular heartbeat, muscle tremors in your hands, insomnia (sleep problems)
  • Noisy breathing
  • Menstrual changes
  • Rapid and deep breathing
  • Frequent fainting
  • Restlessness/uneasiness
  • Stomach cramps
  • Vomiting of blood
  • Swollen glands
  • Chest pain
  • Cold sores
  • Wounds on your genital and anal areas
  • Anxiety
  • Severe lower back pain
  • Loss of bowel or bladder control
  • Impotence
  • Loss of interest in sexual activity
  • Dermatitis
  • Migraines
  • Dark urine
  • Unusual sweating

However, the list above does not exhaust all the possible side effects that accompany nelfinavir. If you observe any of the effects indicated or even those not included in the list above, contact your healthcare provider immediately. Take note that some of the side effects diminish as your body gets accustomed to the medication hence they do not require medical attention. Consult your healthcare provider for instructions and medical advice on side effects or report to the FDA.


Nelfinavir is administered in the form of tablets of 250mg and 625mg or oral powder of 50mg/g. The standard dose administered for an adult with HIV infection is 1250mg orally two times a day. It may also be taken as 750mg tablets orally three times a day. The usual dose for children with HIV infection is as follows: those between two and 13 years old should take 45 to 55 mg/kg orally two times a day or 25-35mg/kg orally three times a day. Nelfinavir is not recommended for children below two years of age. The maximum dose is 2500mg per day.

The nelfinavir tablets should always be taken with a meal to ensure optimal absorption. You are recommended to take the pill when whole, but for young children or patients who have trouble swallowing tablets, you may dissolve the pill in a small amount of water. Then, swirl the liquid to dissolve and fully mix. Once it dissolves, consume the solution immediately. Rinse the glass with a bit more water and take the residual water to ensure you obtain the complete dose. Also, the tablets can be pounded and then mixed with a little food and consumed immediately as an alternative to the oral powder. Avoid mixing nelfinavir with acidic foods or juices (such as apple juice/sauce or orange juice) as mixture may result in a sour taste.

The other option is the 50mg/g oral powder dose which you are supposed to mix with your liquid of choice before taking. You are required to measure the prescribed powder dose using the scoop provided and put it inside a glass. To the dose, add a small amount of water, milk, formula, soy milk/formula or a dietary supplement and consume immediately. Rinse the glass with some more liquid and drink to get the full dose. Take the entire dose of nelfinavir as soon as you mix it but ensure you store the mixture under refrigeration for a maximum of 6 hours if it is not consumed immediately. The oral powder should not be reconstituted with water in its original container but in a separate container.

If by any chance you miss a dose, take the missed dose as soon as you remember. However, if your next scheduled dose is close, skip that dose. Never take additional medicine in a bid to compensate for the missed dose. In the case of an overdose, you should get emergency medical attention from your doctor or contact the nearest poison control centre. You may also call the poison helpline at 1-800-222-1222. Make sure you take nelfinavir together with other HIV medicines. Refer to the drug label for additional information on how to take nelfinavir.

Major drug interactions

If two drugs are taken concurrently, they may alter each other's effect on the body as they interact. Nelfinavir can decelerate the elimination of certain drugs from the body affecting how they work while other medications may have the same effect towards nelfinavir when an interaction occurs. You should take caution when using nelfinavir in combination with other drugs as it could lead to adverse effects on your body.

Nelfinavir has quite a number of drugs that may affect its action or that it may interact with it. Among them are prescription medication, over-the-counter (OTC) drugs, vitamins, and supplements.
Below is a compiled list providing as much information as possible about the major drug interactions of nelfinavir.

  • Alfuzosin
  • Amiodarone
  • Cisapride
  • Cobimetinib
  • Conivaptan
  • Dexlansoprazole
  • Dihydroergotamine
  • Dihydroergotamine intranasal
  • Eliglustat
  • Elvitegravir/codicistat/emtricitabin df
  • Ergonovine
  • Esomeprazole
  • Etravirine
  • Flibanserin
  • Ivabradine
  • Rabeprazole
  • Regorafenib
  • Rifampin
  • Salmeterol
  • Sildenafil
  • Simvastinin
  • St john wort
  • Triazolam
  • Venetoclax
  • Acalabrutinib
  • Afatinib
  • Amiodarone
  • Apixaban
  • Astemizole
  • Atorvastanin
  • Avanafil
  • Axitinib
  • Bedaquiline
  • Bosentan
  • Bosutinib
  • Brexpiprazole
  • Brigatinib
  • Cabergoline
  • Cabozantinib
  • Carbamazepine
  • Ceritinib
  • Cimetinide
  • Cisapride
  • Clarithromycin
  • Copanlisib
  • Dabrafenib
  • Daclatasvir
  • Dronedarone
  • Edoxaban
  • Eletriptan
  • Eluxadoline
  • Macitentan
  • Medroxyprogesterone
  • Mefloquine
  • Midostaurin
  • Neratinib
  • Olaparib
  • Osimertinib
  • Oxycodone
  • Palbociclib
  • Pazopanib
  • Pimavanserin
  • Pomalidomide
  • Ponatinib
  • Quinidine
  • Ranolazine
  • Red yeast rice
  • Ribociclib
  • Rifabutin
  • Rifapentine
  • Riociguat
  • Romidepsin
  • Rosuvastatin
  • Ruxolitinib
  • Vorapaxar
  • Voriconazole
  • Abacavir
  • Abemacicib
  • Abiraterone
  • Acarbose
  • Albiglutide
  • Alitretinoin
  • Almotriptan
  • Alprazolam
  • Amitriptyline
  • Amobarbital
  • Aprepitant
  • Aripiprazole
  • Armodafinil
  • Artemether/lumefantrine
  • Atazanavir
  • Atovastatin
  • Bazedoxifene
  • Betrixaban
  • Bexarotene
  • Bortezomib
  • Bosutinib
  • Brentuximab vedotin
  • Bromocriptine
  • Budesonide
  • Clarithromycin
  • Clobetasone
  • Clomipramine
  • Clonazepam
  • Clopidogrel
  • Clotimazole
  • Clozapine
  • Cocaine
  • Colchicine
  • Conivaptan
  • Conjugated estrogens
  • Cortisone
  • Crizotinib
  • Crofelemer
  • Cyclosporine
  • Dabiagatran
  • Dichlorphenamide
  • Diltiazem
  • Dofetilide
  • Doxorubicin
  • Dronabinol
  • Dronedarone
  • Dyphylline
  • Efavirenz
  • Eletrptan
  • Eliglusat
  • Eluxadoline
  • Elvitegravir
  • Erlotinib
  • Etonogestrel
  • Etoposide
  • Eucalyptus
  • Famotidine
  • Felodipine
  • Fesoterodine
  • Fluconazole
  • Fludrocortisone
  • Flurazepam

Take note that your doctor or healthcare provider has all the information on any drugs that could interact with nelfinavir as this list is not all-inclusive. Inform your doctor of any medicines you are currently using but do not change, start or stop the prescription of any medicine without consulting with your doctor first.


Nelfinavir is not likely to cause harm to an unborn child but if you are planning to get pregnant or are already pregnant let your doctor know for the proper procedure to be taken. Nelfinavir should only be administered when the prospective benefits overshadow the threats. HIV-infected mothers should not breastfeed at all due to the possible risk of transmitting HIV to the uninfected baby. However, there is no evidence of nelfinavir passing into breast milk.

To make sure nelfinavir is safe for you, inform your health care provider whether you are allergic to nelfinavir or any other medication. Let your doctor know of any health conditions you could be having like haemophilia A or B as it could lead to increased bleeding; diabetes or high blood sugar as the drug may raise blood sugar, kidney disease, high cholesterol or triglycerides or liver disease. Individuals with severe liver complications should avoid using this medication. Also, inform your doctor in case you are diagnosed with phenylketonuria (PKU). This is because the nelfinavir oral powder is made with an artificial sweetener (aspartame) which contains phenylalanine that may be unsafe to people with phenylketonuria.

Nelfinavir can make different forms of hormone-based birth control pills or implants less efficient. During treatment with nelfinavir, you should use a secondary/non-hormonal birth control means like condoms along with the hormone-based ones to avoid pregnancy. Your doctor can give you advice on ways of adjusting your birth control methods while taking nelfinavir.

Nelfinavir can have an effect on the way other products or medicines work and other medicines can affect how nelfinavir works. Therefore let your doctor know about any other non-prescriptions and prescription medicines, dietary supplements or herbal products you may be using to avoid occurrence of serious or detrimental side effects which may be caused by major drug interactions. During treatment with nelfinavir, make sure you keep all your appointments with your healthcare practitioner. Use nelfinavir only in emergency situations when there is no safer drug option. The medication is not recommended for use by any person younger than 2 years old and use with care for children.

Read and understand all the drug guides, patient information, and instruction leaflets provided to you while on this medication. Follow strictly all directions given by your healthcare provider on the prescription. Ensure you neither exceed nor reduce the amount recommended for the dose to control your infection effectively. Take the prescription with fatty foods but avoid acidic food and drinks. Also ensure you get your prescription topped up before your medicine completely runs out. Every individual diagnosed with HIV and AIDS should stay under the care of a health specialist as you may need regular medical follow up sessions and blood tests. Take note that this medicine will not stop you from transmitting HIV to other people. You should therefore avoid engaging in unprotected sex or sharing personal effects like toothbrushes or razors. Talk to your healthcare provider about safe measures to take to prevent transmission of the virus.


Store the nelfinavir tablets and oral powder at room temperature, 59-86 degrees Fahrenheit (15-30 degrees Celsius). Store the medicine in a cool, dry place away from heat or direct light. Keep nelfinavir in its original container and make sure it remains tightly closed. Beware not to take nelfinavir if the seal is broken or if the container opening is missing because the contents may not be safe for use. Store the solution after mixing under refrigeration for no more than 6 hours, but if it exceeds this time, discard it.

Discard or get rid of nelfinavir that is no longer in use or expired (out of date) appropriately. Ensure you consult your healthcare provider on how to safely dispose of unused drugs if you don't know how. Nelfinavir and all drugs should be kept out of reach of children and pets.


Nelfinavir is an antiviral prescription medication that prevents human immunodeficiency virus (HIV) cells from increasing in your body by inhibiting the action of protease enzyme. It belongs to a drug class known as Protease Inhibitors (PIs).

When HIV infects a cell it makes copies of itself, it then uses an enzyme called protease to place itself properly so that it can be released from the cell into other cells infecting them. Nelfinavir's mechanism of action as an HIV Protease Inhibitor is by blocking the enzyme protease. This therefore prevents the virus from multiplying and may also eventually reduce the amount of HIV (viral load) in the body.

It is in the form of a tablet or oral powder and is administered orally. You are required to take the drug dose as prescribed by your doctor avoiding under or overdosing to obtain optimum benefits. HIV infected persons are required to remain under the care of a doctor for constant follow up sessions. Nelfinavir presents some adverse or minor side effects which can be handled by your doctor. Take note of the major and minor drug interactions and contraindications of nelfinavir as it is crucial when using the drug. Proper preparation, usage, storage and disposal of the drug should be observed. Nelfinavir is normally prescribed in combination with other antiretroviral drugs in the treatment of HIV in both children and adults. However, it should not be mistaken as a cure for HIV or AIDS. Such medications don't cure HIV; they only reduce the risk of transmitting the virus and help the infected individuals to it live longer and healthier lives.