tpan.com - Drug Guide 2005

Two 625 mg tablets twice daily
	Brand name: Viracept Common name: nelfinavir Class: HIV protease inhibitor (PI) Standard dose: 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 dose. Viracept Oral Powder also available for children and individuals unable to swallow tablets. AWP: $756.66 / month for 625 mg Manufacturer contact: Agouron Pharamaceuticals, a Pfizer company, www.viracept.com, 1 (888) 777–6637 AIDS Treatment Information Service: 1 (800) HIV–0440 (448–0440)
Potential side effects and toxicity: Most common include diarrhea (15-20% of patients in Study 542), stomach discomfort, nausea, gas, weakness and rash. As seen with all other protease inhibitors are increased levels of cholesterol and triglycerides, except possibly unboosted Reyataz (atazanavir) and these increased levels may be associated with heart disease. Other possible side effects 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. Potential drug interactions: In general, less severe interactions compared to other drugs in this class. Do not take with Tambocor (flecainide), Rythmol (propafenone), Versed, Cordarone (amiodarone), Halcion, Hismanol, Seldane, rifampin, ergot derivatives (such as Cafergot, Wigraine and Methergine, D.H.E. 45, in any form—serious interactions seen with dilation during gynecological exams), garlic supplements, or the herb St. John’s wort. Do not use Zocor (simvastatin) or Mevacor (lovastatin); lipid-lowering alternatives are Lipitor (atorvastain), Lescol, and Pravachol (pravastatin), but they should be used with caution due to potential for liver toxicity. Rifampin and Viracept should not be used together. Blood levels of Viracept are reduced by rifampin and may be reduced by phenobarbital, phenytoin, and carbamazepine (Tegretol and others). Fortovase levels increase three-to-five-fold, Crixivan increases 50% (see Crixivan for potential drug interactions). Mycobutin (rifabutin) dose must be decreased when used with Viracept. Prescriber may need to adjust doses of any of these drugs accordingly. Protease inhibitors increase blood levels of Viagra (sidenafil citrate), Cialis (tadalafil) and Levitra (vardenafil). Use with caution. Initially the Viagra dose should be 12.5 mg (1/2 of 25 mg tablet) and increased as needed and tolerated. It’s recommended that people on PIs do not exceed 25 mg of Viagra in a 48-hour period because of potential for serious reaction. Use Cialis at reduced doses of 10 mg every 72 hours and Levitra at reduced doses of no more than 2.5 mg every 72 hours, with increased monitoring for adverse events. The effectiveness of birth control pills may be decreased when taking Viracept; women and their male partners should consider the use of alternative contraception methods with barrier. Tips: Do not leave pharmacy without anti-diarrhea meds such as Immodium, 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. Patients can crush adult tablets for use in children 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. Examples of meals that help to get to adequate food intakes include: Taco Bell Breakfast Burrito and 8 oz of non-acid juice (650 calories, 35% from fat) or Subway Tuna Sandwich including potato chips and 8 oz of skim milk (703 calories, 41% from fat).
Doctor Viracept at one time surpassed Crixivan as the most commonly prescribed PI. Today, it has been surpassed by other PIs. However, when it was first marketed, it could be taken with food, a distinct advantage over Crixivan. Moreover, the Crixivan-associated kidney stones were not a problem. Once prescribed three times daily, studies demonstrated that it could be given twice a day. Its main drawback is diarrhea, which can be explosive and unpredictable. In head-to-head trials with other PIs, Viracept appears to be less potent which, along with its annoying gastrointestinal side effect, has contributed to its decline in use. —Ross Slotten, MD
Activist Anecdotally, people say the new formulation is easier on the gut than the old one. On the face of it, that’s not saying much—the old one was b-a-d—but people really seem to tolerate the 625 mg pills much better. In my years with nelfinavir, I pretty much mastered the gut issues; it was the lipid kick that did me in. Its impact on blood fats doesn’t set it apart from most other PIs, but it must be considered if long-term survival, sans heart attacks, is the goal. Regarded as a potency weakling, it’s used like a sparring partner for other PIs in studies. Companies pit their new drugs against nelfinavir in what amounts to a lame “at least we’re no worse than the weakest one!” trial design. It’s a recommended agent for use in pregnancy and it may get a second life in the world of double PI therapy, so don’t count it out. —Heidi M. Nass

Fusion Inhibitor | Fuzeon / T-20 / enfuvirtide |

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