Viracept

Protease Inhibitor

Common Name: nelfinavir (NFV)

Brand Name: Viracept

Class: HIV protease inhibitor (PI)

Standard dose: 1,250 mg taken as either two 625 mg tablets or five 250 mg tablets twice daily 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: $640.92 / month for 625 mg

Manufacturer contact: Agouron Pharmaceuticals, 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 (except unboosted Reyataz), there can be increased levels of cholesterol and triglycerides 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. Invirase levels increase three-to-five-fold and Crixivan increases 50% (see Crixivan for potential drug interactions), so dose adjustments may be needed. Do not take with oral Versed (midazolam), Cordarone (amiodarone), Halcion (triazolam), Rifadin (rifampin), Prilosec-OTC (omeprazole), ergot derivatives (such as Cafergot, D.H.E. 45, Methergine, Wigraine), 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. Use calcium channel blockers with caution.

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. 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 or 2.5 mg Levitra per 72 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.

Doctor

Viracept (nelfinavir) was approved (three tablets three times daily) for use in combination with other antiretroviral drugs in the treatment of HIV infection in 1997. In 2003, the dosage formulation of nelfinavir was changed to two tablets twice daily. The level of drug in the bloodstream is increased when taken with food. We used a lot of nelfinavir when it came to market. Diarrhea was its most prominent problem (20% of our patients) and we tried all sorts of tactics to plug the ?hole in back? -- calcium ingestion, more food, scheduled anti-diarrhea drugs, etc. Nelfinavir had a good antiviral effect and most patients just endured the problem. Interestingly, nelfinavir is one protease inhibitor that is not boosted by low-dose ritonavir. HAART therapy containing nelfinavir was the combination of choice for pregnant women until recently. The concern that nelfinavir may have been contaminated with cancer-producing chemicals was a major blow to use of this drug in pregnancy. With newer protease inhibitors available with better tolerability and fewer pills to ingest, nelfinavir use has significantly decreased. -- Frank M. Graziano, M.D., Ph.D.

Activist

Viracept can cause inconvenient and intermittent explosive diarrhea! But that's just the bias of my personal experience. To be fair, the gastrointestinal distress is supposedly less extreme with the new formulation -- and thankfully, fewer pills; but its significant number of drug-drug interactions remains a concern. Viracept is the only PI that does not require boosting and it seems to work well in preventing mother-to-child transmission in pregnant patients and those with bad livers. But, I'd at least think twice before opting for this drug: it is no longer recommended by the DHHS Guidelines Panel for initial therapy. -- Morris Jackson

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