Nelfinavir
Nelfinavir is an HIV-1 protease inhibitor used in combination with other antiretroviral medicines to treat HIV-1 infection.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Nelfinavir: Patient Information Guide
A plain-language walkthrough of Nelfinavir — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Nelfinavir is an antiretroviral medicine used to treat HIV-1 infection.
- Viracept tablets are approved for the treatment of HIV-1 infection in adults and adolescents 13 years and older, always used in combination with other antiretroviral medicines
- Viracept 250 mg tablets are also used in children aged 2 to less than 13 years, with doses adjusted for body weight
- Nelfinavir is never used as the sole HIV medicine — combination therapy is required
⚙️How it works▾
Nelfinavir works by blocking HIV-1 protease, an enzyme the virus depends on to finish building new copies of itself. When this enzyme is blocked, HIV can only produce immature, non-infectious viral particles — so the virus cannot spread to new cells. This helps lower the amount of HIV in your body and supports your immune system.
Like other antiretrovirals, nelfinavir must be taken consistently and in combination with other HIV medicines to prevent the virus from developing resistance — meaning the virus mutating in ways that make the drug stop working.
💊How it's taken▾
Viracept tablets are taken by mouth, either twice daily or three times daily. Always take every dose with a meal — food substantially increases absorption and reduces variability in drug levels. Adults or adolescents who cannot swallow tablets may dissolve them in a small amount of water. For children aged 2 to less than 13 years, dosing is based on body weight, and a prescriber will determine the right number of tablets per dose.
- Take with a full meal, not just a snack, for best results
- If also taking didanosine, take Viracept with food and give didanosine either 1 hour before or 2 hours after Viracept
- Do not stop taking Viracept without speaking to your prescriber first
🤒Side effects — in detail▾
The most commonly reported side effects with Viracept are:
- Diarrhea — very common, usually mild to moderate
- Nausea
- Gas (flatulence)
- Skin rash
- Abdominal pain
- Loss of appetite
- Headache
- Dizziness or sleep difficulty
More serious reactions that require prompt medical attention include signs of liver problems (yellowing of skin or eyes, dark urine), severe allergic reactions (breathing difficulty, swelling, severe rash), new or worsening high blood sugar, unusual bleeding (especially if you have hemophilia), and mood changes or thoughts of self-harm.
⚠️Warnings & precautions▾
- Drug interactions: Viracept interacts with many medicines. Some combinations — including rifampin, St. John's wort, certain sedatives, heart rhythm drugs, and cholesterol medications — are completely prohibited. Always share a full medication list with every provider.
- Liver disease: Viracept must not be used in people with moderate or severe liver disease. Liver problems, including elevated enzymes and liver failure, have been reported, particularly in pregnancy.
- Blood sugar changes: New or worsening diabetes and high blood sugar have been reported. Diabetic ketoacidosis (a dangerous complication of uncontrolled diabetes) has occurred. Monitor blood sugar closely.
- Hemophilia: Increased or spontaneous bleeding has been reported in people with hemophilia types A and B taking protease inhibitors.
- Body fat changes: Some people on antiretroviral therapy notice shifts in where body fat is stored — fat may accumulate in the belly or back of the neck, while the face or limbs become thinner.
- Immune reconstitution syndrome: After starting treatment, a recovering immune system can trigger inflammation in response to previously hidden infections. Tell your doctor about any new fever or symptoms after beginning therapy.
🔀What it interacts with▾
Nelfinavir affects, and is affected by, a wide range of other medicines — some combinations are dangerous and must be avoided entirely.
- Completely avoid (contraindicated): rifampin, St. John's wort, lovastatin, simvastatin, amiodarone, quinidine, pimozide, lurasidone, triazolam, oral midazolam, ergot derivatives (e.g., ergotamine), cisapride, alfuzosin, and sildenafil (Revatio) when used for pulmonary arterial hypertension
- Proton pump inhibitors (e.g., omeprazole): can significantly reduce nelfinavir levels, risking treatment failure and resistance
- Anticonvulsants (carbamazepine, phenobarbital, phenytoin): may lower nelfinavir levels; phenytoin levels also need monitoring
- Birth control pills: nelfinavir can lower hormone levels, making oral contraceptives less reliable — use additional or alternative contraception
- Erectile dysfunction drugs (sildenafil, vardenafil, tadalafil): much lower doses required; risk of dangerous low blood pressure and other serious side effects
- Trazodone: nelfinavir raises trazodone levels — use with caution and consider a lower dose
- Methadone: nelfinavir may lower methadone levels — dose may need adjustment
- Immunosuppressants (cyclosporine, tacrolimus, sirolimus): levels of these drugs may rise significantly; close monitoring needed
- Salmeterol (inhaled): concurrent use is not recommended due to increased cardiovascular risks
- Warfarin: nelfinavir may affect warfarin levels — INR (blood-thinning measure) needs careful monitoring
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Tell your doctor if you have moderate or severe liver disease — Viracept is not safe to use in these situations
- If you are pregnant, discuss carefully with your doctor — liver complications and a potential increase in birth defect rates have been observed; alternative HIV medicines are often preferred during pregnancy
- Do not breastfeed — HIV can be passed to infants through breast milk
- Tell every prescriber and your pharmacist about all medicines, vitamins, and herbal supplements you take — the interaction list for Viracept is extensive
- If you have diabetes or are at risk for high blood sugar, monitor your glucose levels closely while on this medicine
- If you have hemophilia (type A or B), alert your doctor — increased bleeding risk has been reported with protease inhibitors
- If your child has phenylketonuria (PKU), note that the Viracept oral powder formulation contains phenylalanine; the tablet form does not carry this concern
🚑If you take too much▾
There is no specific antidote for a Viracept overdose. If an overdose is suspected, removing unabsorbed medicine (through vomiting or gastric lavage) and giving activated charcoal may help limit absorption. Because nelfinavir binds very strongly to proteins in the blood, dialysis is unlikely to remove meaningful amounts of the drug.
📡Pharmacodynamics — effects in the body▾
Nelfinavir blocks the HIV-1 protease enzyme, preventing the virus from producing mature, infectious particles. At recommended doses, studies in healthy volunteers showed that Viracept does not cause clinically meaningful changes in heart electrical conduction (specifically, the QTc interval — the part of the heart's rhythm cycle that, when prolonged, can trigger dangerous arrhythmias). Even at higher-than-normal doses tested in studies, no subject exceeded the threshold for concerning QTc prolongation.
🔬Pharmacokinetics — how your body processes it▾
Nelfinavir is absorbed through the gut after oral dosing, and food — particularly higher-calorie or higher-fat meals — substantially increases the amount that reaches your bloodstream. It is highly protein-bound (over 98%), meaning most of the drug in blood is attached to proteins rather than circulating freely. Nelfinavir is mainly broken down in the liver by enzymes called CYP3A and CYP2C19, which is why so many drug interactions exist. The drug and its active metabolite are primarily eliminated through the feces.
📦How to store it▾
stored at 15° to 30°C (59° to 86°F). Dispense in original container .
📄 Written from Nelfinavir’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Nelfinavir
153 supplements and herbal products have documented interactions with Nelfinavir in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 3
- Moderate · 113
- Minor · 37
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Nelfinavir — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Viracept used for? ▾
Do I really need to take it with food every time? ▾
What side effects should I expect, and when should I actually call my doctor? ▾
Are there medicines I absolutely cannot take with this? ▾
Is it safe to take if I'm pregnant or trying to get pregnant? ▾
I have diabetes — is there anything special I need to watch out for? ▾
Is Nelfinavir available over the counter? ▾
When was Nelfinavir first available? ▾
💬 Answers drafted from Nelfinavir’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Nelfinavir comes
Nelfinavir is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Tablet
How this form is used
- Viracept tablets are used to treat HIV-1 infection in adults and adolescents 13 years and older, in combination with other antiretroviral medicines
- Viracept 250 mg tablets are also used for children aged 2 to less than 13 years, with dosing based on body weight
- Viracept tablets must be taken with a meal to ensure proper absorption
- Adults and adolescents who cannot swallow Viracept tablets may dissolve them in a small amount of water before taking
- Children 2 to less than 13 years who cannot swallow Viracept 250 mg tablets may also have them dissolved in water; follow your child's prescriber for the correct number of tablets per dose
- Take Viracept exactly as prescribed — either twice daily or three times daily — and do not skip doses
📊 Nelfinavir across the U.S. market
How Nelfinavir appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
🔍 Compare Nelfinavir products
A representative set of FDA-listed product records for Nelfinavir — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 250 mg | Oral | Agouron × 3 listings | NDA | View NDC → |
| 625 mg | Oral | Agouron × 3 listings | NDA | View NDC → |
Showing 6 of 6 products — FDA National Drug Code Directory. See every product, package size and price: browse all 6 Nelfinavir NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Nelfinavir — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Nelfinavir in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Nelfinavir went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 134527 2 dose forms · 3 strengths
-
Dose form (SCDF) Oral Powder RxCUI 378235No current FDA listingClinical drug / strength (SCD) 0.05 MG/MGRxCUI 311925 -
Dose form (SCDF) Oral Tablet RxCUI 373015In current FDA listings
Look up RxCUI 134527 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Nelfinavir is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Nelfinavir belongs to the Protease Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Agouron is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.