Crixivan

Protease Inhibitor

Common Name: indinavir sulfate (IDV)

Brand Name: Crixivan

Class: HIV protease inhibitor (PI)

Standard dose: Rarely used by itself (two 400 mg capsules every eight hours with no food or a low-fat snack). Almost always boosted with Norvir, both twice daily: 400 mg Crixivan + 400 mg Norvir; 800 mg + 100 mg; or 800 mg + 200 mg (all doses taken with food, and with plenty of water to avoid kidney sludge or stones). Take missed dose as soon as possible, but do not double up on your next dose. Also available in 100 mg, 200 mg and 333 mg capsules.

AWP: $570.95 / month for 400 mg, 180 capsules

Manufacturer contact: Merck and Co.,
www.crixivan.com, 1 (800) 850-3430

AIDSInfo:
1 (800) HIV-0440 (448-0440), www.aidsinfo.nih.gov

Potential side effects and toxicity: Headache, fatigue or weakness, malaise (general ill feeling), nausea, diarrhea, stomach pains, loss of appetite, yellowing of skin/eyes, changed skin color, dry mouth/sore throat, taste changes, painful urination, indigestion, joint pain, hives, and liver toxicity. Itchy/dry skin, ingrown toe nails, and hair loss are unique to Crixivan. Kidney stones, which may lead to more serious problems, can also occur -- if pain develops in the middle to lower stomach or the back, or if there is blood in the urine, call your health care provider immediately. An increase in bilirubin (a test of liver function) has been reported, but it is not associated with liver problems. It may sometimes cause yellowing of the skin or eyes. 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: Do not take with Tambocor (flecainide), Rythmol (propafenone), Cordarone (amiodarone), midazolam, triazolam, rifampin, pimozide, ergot derivatives (such as Cafergot, Wigraine, Methergine, and D.H.E. 45), garlic supplements, or the herb St. John's wort. Do not use simvastatin, Vytorin, or lovastatin; lipid-lowering alternatives are Lipitor, Lescol, and pravastatin, but they should be used with caution due to potential for liver toxicity.

Not recommended in combination with Reyataz. Reduce Crixivan to 600 mg every eight hours when taken with Rescriptor, itraconazole (200 mg twice a day), or ketoconazole (200 mg once a day). The dose of Mycobutin should be reduced by 50% and Crixivan dose increased to 1,000 mg every eight hours when taken together.

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.

Effectiveness of birth control pills may be decreased; consider the use of alternative or additional contraception. Additional monitoring may be required when taking Coumadin (warfarin), immunosuppressants, or calcium channel blockers (such as Norvasc, Procardia, and others). Carbamazepine (Tegretol and others), Dilantin (phenytoin), or phenobarbital may decrease Crixivan, so alternate seizure medications should be used. Crixivan may decrease levels of methadone but withdrawal rarely occurs. Methadone doses may need to be increased. Also, increased levels of trazodone (Desyrel) can occur with Crixivan. Increased levels of the inhaled and nasal sprays with fluticasone, a steroid for asthma or allergies (found in Advair, Flonase, and Flovent) can occur with Crixivan and therefore should be used with caution.

Tips: Drink at least 48 oz. of fluids daily, preferably water or clear liquids (soda pop doesn't count!) to decrease the chances of a kidney stone. Don't forget to drink more water in summer or with increased sweating. Large amounts of coffee or alcohol can increase risk of stones due to increased dehydration. Stones may continue after stopping Crixivan. Grapefruit juice decreases Crixivan blood levels. Store in original container and keep dry. Please see package insert for more complete potential side effects and interactions.

Doctor

Crixivan (indinavir, known to many as Crix) was approved for use with other antiretroviral drugs in HIV infection in 1996. While we were trying to figure out what to do with Invirase, Crixivan became a major choice for our patients. Dietary restriction with use of this drug was an issue for some. Two capsules had to be ingested every eight hours on an empty stomach. I can remember vividly patients having great difficulty taking the regimen (Crixivan without food, other drugs with food), but how could they stop? They were better. Crixivan helped many of our patients and the number dying in our practice dropped significantly. The dosing is now easier (two capsules twice daily with one ritonavir twice daily -- no food restrictions), but we rarely use the drug. General gastrointestinal side effects occurred in 10-15 % of our patients. Other complications, not as common, but significant, were kidney stones and kidney failure. We asked our patients to drink lots of water (almost to the point of wanting to "pee" all the time) to avoid kidney stones. "Crix belly" (increased abdominal girth) was the rage for a while. Of course we later learned this was lipodystrophy and not specific to Crixivan. I still have a few patients on Crixivan and they refuse to go off the drug ("I'm doing okay -- why?"). Crixivan served our patients well during a very difficult time. -- Frank M. Graziano, M.D., Ph.D.

Activist

Back in the day (1996), Crixivan was part of "the cocktail" that rescued us from the brink of death, thus ushering in the era of HAART (Highly Active Antiretroviral Therapy). And because it was saving us, we didn't care that we had to schedule our lives around Crixivan. It had to be taken every eight hours and came with food restrictions and liquid intake requirements: take on an empty stomach, an hour before or two hours after eating a high-fat meal, and drink 64 ounces of water a day or you could very well get kidney stones, one of its highly possible side effects. Crixivan came to be associated with fat redistribution, thus the old monikers "Crix belly" and "buffalo hump" that we now call lipodystrophy. Crixivan is the granddaddy of the PIs and lives in retirement and in the memories of those of us who reaped its benefits. -- Morris Jackson

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