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Class: HIV protease inhibitor (PI)
Standard dose: 1,200 mg taken as either two 625 mg tablets or five 250 mg tablets twice-a-day with food. Take a missed dose as soon as possible, but do not double up on your next dose. Viracept Oral Powder also available for children and individuals unable to swallow tablets.
AWP: $726.40 / month for 625 mg
Manufacturer contact: Agouron Pharamaceuticals, a Pfizer company,
www.viracept.com, 1-800-879-3477 (TRY-FIRST)
AIDSInfo:
1 (800) HIV–0440 (448–0440), www.aidsinfo.nih.gov
Potential side effects and toxicity: Most common include: diarrhea (30–40% of patients), stomach discomfort, nausea, gas, weakness, and rash. As seen with other protease inhibitors, there can be increased levels of cholesterol and triglycerides (except possibly unboosted Reyataz) which may be associated with an increased risk of heart disease. Other possible side effects seen with protease inhibitors are lipodystrophy (body fat changes, including thinning of the face, arms and legs, with or without fat accumulation in the stomach, breasts and sometimes the upper back), onset of new cases or worsening of diabetes (see your doctor promptly), and increased bleeding in hemophiliacs. Immune Reconstitution Inflammatory Syndrome (IRIS) may occur as the immune system regains strength; report symptoms of illness, such as shingles and TB, to health care provider.
Potential drug interactions: In general, less severe interactions compared to other drugs in this class. Do not take with Versed (midazolam), Cordarone (amiodarone), Halcion (triazolam), Rifadin (rifampin), Prilosec (omeprazole), ergot derivatives (such as Cafergot, Wigraine and Methergine, D.H.E. 45, in any form), garlic supplements, or the herb St. John’s wort (hypericum perforatum). Do not use Zocor (simvastatin), Vytorin or Mevacor (lovastatin); lipid-lowering alternatives are Lipitor (atorvastatin), Lescol (fluvastatin), and Pravachol (pravastatin), but they should be used with caution due to potential for liver toxicity. Viracept may decrease methadone levels but withdrawal rarely occurs; methadone doses may need to be increased.
Blood levels of Viracept are reduced by rifampin and may be reduced by phenobarbital, phenytoin, and carbamazepine (Tegretol and others), so it is important to inform your doctor if you are taking any of these medications. Invirase levels increase three-to-five-fold and Crixivan increases 50% (see Crixivan for potential drug interactions), so dose adjustments may be needed. Mycobutin (rifabutin) dose must be decreased when used with Viracept. Prescriber may need to adjust doses of any of these drugs accordingly.
Cialis, Levitra, and Viagra levels are increased; doses should not exceed 10 mg Cialis per 72 hours, 2.5 mg Levitra per 24 hours, or 25 mg Viagra per 48 hours.
Increased levels of the inhaled and nasal sprays with fluticasone, a steroid for asthma or allergies (found in Advair, Flonase, and Flovent), can occur and therefore should be used with caution. The effectiveness of birth control pills may be decreased; women and their male partners should consider the use of alternative or additional contraception methods. Also, increased levels of trazodone (Desyrel) can occur. A lower dose of trazodone is recommended.
Tips: Do not leave pharmacy without anti-diarrhea meds such as Immodium, or Tums or other calcium products. Taking a 500 mg calcium supplement with doses hugely decreases diarrhea. Also try Solgar oat bran tablets, psyllium husk fiber bars and pancreatic enzymes (all with meals). As an extra precaution, take a change of clothes with you everyday for the first several weeks—stick it out, most often symptoms improve after two or three weeks. The oral powder tastes horrible and requires a large amount for mixing into food. Ethyl methanesulfonate (EMS) is a process-related impurity in Viracept. In June 2007, excess levels of EMS detected in Viracept caused recall of the product in Europe. So far EMS has not been detected at high levels in the U.S. Exposure to EMS can potentially increase the risk of cancer in adults. As a precaution, the maker of Viracept is not recommending to start Viracept in pediatric patients and pregnant women.
People using Viracept can crush adult tablets or dissolve tablets in a small amount of water. Acidic food or juice (e.g. orange/apple juice or apple sauce) not recommended in combination with Viracept, due to resulting bitter taste. To get the full benefit of Viracept by increasing its level in the body, it must be taken with a meal of at least 500 calories, with at least 20% to 50% of those calories coming from fat. Please see package insert for more complete potential side effects and interactions.
Once upon a time, Viracept was the “kindler, gentler” PI, because it was easier to take (only five chalky tablets twice a day!) and was better tolerated (if you didn’t mind lots of diarrhea) than its biggest competitor, Crixivan. Its other claim to fame was that cross-resistance wasn’t as bad when you failed Viracept than when you failed other PIs. All that was true—it really was an improvement over what was out there at the time. But the standard of care has changed, leaving poor Viracept in the dust. Today, all PIs—with the lone exception of Viracept—are given with a low “boosting” dose of Norvir. This makes them more effective and means that rather than getting better mutations, you get no mutations at all. Most can be given once a day, and they all cause less diarrhea than Viracept. Just about every drug that’s been compared with Viracept has come out on top. Until recently, the only remaining argument for the use of this drug was that it had a good safety record in pregnancy. But now that a carcinogen has been found in Viracept tablets, it’s no longer recommended for pregnant women, either. I can’t think of a good reason anymore to use this once very important drug.—Joel Gallant, M.D.
Viracept (nelfinavir) is one of the older protease inhibitors and is not widely used today. Viracept was relatively easy to use, not yet known to contribute to cholesterol problems, and relatively non-toxic. Its worst defect was that it caused diarrhea, which didn’t sound all that bad. Over time though, daily diarrhea became intolerable to many people. There was also a nagging suspicion that Viracept just wasn’t as potent as Crixivan. The drug sold well for a number of years, but only until something better came along. The solution, Kaletra, demonstrated fewer problems and greater potency and it quickly came to dominate the market, pushing Viracept on to the back shelf. An improved formulation of Viracept helped a bit with the diarrhea but by then it was too late to regain its position in the HIV marketplace. Though still available today, Viracept is seldom used. —Martin Delaney
