Crixivan® (Indinavir)

Who should take this?

People with HIV who have developed some resistance to either NRTIs or protease inhibitors may be given Crixivan with two NRTI drugs and one non-nucleoside reverse transcriptase inhibitor (NNRTI). Sometimes, if a person has a great deal of resistance to NRTI drugs or isn’t able to tolerate them, Crixivan may be given with just one NNRTI.

Crixivan can cause problems for people who have hemophilia, kidney or liver disease or a history of alcohol abuse.

How is it taken? / Dosage

Crixivan is a capsule that is taken by mouth every eight hours – three times a day. It should be taken on an empty stomach one hour before meals or two hours after meals. It should be taken with plenty of water – at least a full eight-ounce glass of water. This will help avoid kidney problems.

If indinavir causes an upset stomach, it can be taken with a light snack such as dry toast or cornflakes with skim milk. It should not be taken with grapefruit juice, which can interfere with how the body absorbs it.

People who take didanosine (ddi or Videx®) should take it on an empty stomach one hour before taking Crixivan.

It is important to drink a lot of water when taking Crixivan – at least six, eight-ounce glasses of water or other liquids every 24 hours.

Crixivan/indinavir should be taken exactly as directed by the doctor. Do not take more or less of it or take it more often than the doctor orders. Continue to take indinavir even if you feel well. Do not stop taking indinavir without talking to your doctor.

Side Effects

Side effects from indinavir are common, including:

• Anemia
• Changes in where fat is on the body. This may include a big belly (protease paunch), enlarged breasts, a fat pad between the shoulders (buffalo hump) and a loss of fat from the arms, legs, face and buttocks.
• Dry skin, mouth and lips
• Feeling tired
• Hair loss
• Headache or dizziness
• High blood sugar and an increased risk of diabetes
• High levels of bilirubin (bile pigments). This may cause the eyes or skin to get yellow.
• Higher cholesterol levels
• Higher liver enzymes, much like with hepatitis
• Higher risk of blood clots in the veins
• Higher risk of heart disease and chest pain
• Higher uric acid, which increases the risk of gout
• Ingrown toenails
• Kidney stones or crystals in the urine. This causes pain in the flank or groin or when urinating. There may also be blood in the urine, nausea, vomiting and sweating. Women are more likely to have kidney stones than men. In rare cases, the stones can lead to life-threatening kidney failure. When this happens it may be necessary to have hemodialysis. (The blood is taken from the blood in a tube, filtered by a machine and then returned to the body in this process.)
• Skin rashes
• Sleepiness or inability to sleep
• Sore throat and nose congestion,
• Stomach pain, nausea, vomiting, acid reflux or heart burn, diarrhea or an altered sense of taste

Women who are or plan to be pregnant should tell their doctors before taking Crixivan. Women with babies should not breast feed while taking Crixivan.

Drug Interactions

Crixivan mixes with some other drugs in a way that can be dangerous. Drugs likely to cause problems when taken with Crixivan are those used to treat:

• Acid reflux/heartburn medications, such as Propulsid® (cisapride)
• Allergies, such as the antihistamines Hismanal® (astemizole) or Seldane® (terfenadine)
• Antibiotics such as Rifadin® (rifampin) or rifadin, rifamate, rifater or rimactane
• Corticosteroid drugs such as dexamethasone (Decadron®), used to treat inflammation
• Depression. Herbs such as St. John's wort, sometimes used to fight depression, should not be taken with Crixivan.
• Heart rhythm irregularities (antiarrhythmics), such as Cordarone® (amiodarone), Tambocor® (flecainide), Rythmol® (propafenone) or Quinaglute®/Quinidex® (quinidine)
• High blood pressure, such as diuretics used to reduce water retention. Taking these drugs along with Crixivan may increase the risk of kidney stones.
• Migraine headaches such as ergot drugs (Cafergot®, Wigraine® (ergotamine) and others)
• Sedatives, such as Versed® (midazolam) and Halcion® (triazolam)
• Seizures such as carbamazepine (Tegretol®); phenytoin (Dilantin®) and phenobarbital

Drug dosages may need to be adjusted to prevent drug interactions when a person is taking Crixivan and any of the following drugs:

• Anti-fungus drugs such as Sporanox® (itraconazole) or Nizoral® (ketoconazole)Drugs to fight tuberculosis or Mycobacterium Avium complex (MAC) such as Mycobutin® (rifabutin)
• Other antiretrovirals such as delavirdine (Rescriptor®), efavirenz (Sustiva®), nevirapine (Viramune®)

Women taking Ortho Novum 1/35 birth control pills should be aware that hormone levels can increase when they are taken with Crixivan.  This may mean that if side effects occur, drugs may have to be changed. It is important that people taking Crixivan tell their doctors and their pharmacists all the drugs that they are taking and all supplements.

Resistance

HIV can adapt and change (mutate).  When this happens drugs that once were effective against HIV no longer are.  The virus has found a way to grow even when the drug is taken properly.  Signs of resistance are an HIV viral load that doesn’t drop.

The virus has to make more than one change (mutation) before it becomes resistant to Crixivan. (Non-nucleoside analog drugs lose their effectiveness with only one change.)  When a resistance builds up against Crixivan, it most often means there will be a resistance to other protease inhibitors. Often Kaletra (lopinavir and ritonavir) or Agenerase (amprenavir) are exceptions to this.