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darunavir - Prezista

General
Information
Darunavir (Prezista) is almost always used as one component of a multidrug combination to suppress the human immunodeficiency (HIV) viral load.
Specifics Darunavir is one of the most potent antiviral drugs against HIV infection.  Darunavir is always combined with another protease inhibitor called ritonavir.

Darunavir works by inhibiting the production of HIV's proteins.  Darunavir is classified as a protease inhibitor (PI) combination.

Dosing Generally darunavir is taken as two (2) 300 mg tablets twice a day with one (1) 100 mg ritonavir (Norvir) gelatin capsule.  Darunavir and ritonavir are always taken with food.  It is very important to take darunavir with food to prevent it from irritating your stomach and bowels. 

Darunavir tablets should be kept at room temperature.

Adherence
(this refers to your willingness, ability, and actual performance in taking your medications)

For further information and tips on adherence, go to the Adherence section of this site.

The "all or none" rule applies to all antiviral medications such as darunavir: you should commit yourself to taking every dose, every day OR take none at all.  Missing doses leads to a worsening of HIV infections (resistance to medications) and makes finding a good antiviral medication harder to do.

As with any antiviral drug or antibiotic, try not to ever miss a dose.  If you miss a dose and notice that you have done so within a few hours of its scheduled time, you may take the dose as usual and take the next dose at its regular time. 

You should never change the dose of darunavir without speaking to your healthcare provider first.

If you miss more than one dose, look at the reasons why you missed them and come up with a plan to avoid it in the future.  For example, if you fell asleep too early, take the medicine earlier in the evening, with your later meal, set an alarm, or have someone appointed to wake you up for your medicine. 

It is strongly recommended that you consider using weekly pill boxes and arrange all of your doses a week in advance.  Buy a small pill box so that you can carry a dose or two of your medicines with you in case you are away from home.

Possible
Side Effects
The package insert for most drugs including darunavir is often overwhelming and scary with perhaps an overemphasis on side effects.  We have summarized the important and more common problems here.

Persons with sulfonamide or sulfa drug allergies should take darunavir cautiously as darunavir contains a sulfa molecule.

Many people take darunavir
without many side effects. 

Possible side effects include rash (7%), stomach upset, diarrhea, nausea, headache, liver problems, increased fat (cholesterol and triglycerides) in the blood, turning yellow with jaundice, numbness of the lips or mouth, and possibly diabetes.

Persons with chronic hepatitis B or C or other liver problems should have their liver tests monitored closely.

Usually you will have blood tests done in the first month to look for the beneficial effects of darunavir and any side effects. 

Many minor side effects will either stay constant or get better with time.  It is mainly the side effects that are severe or get worse that may cause significant health risks for you.

All drugs of this type can cause or contribute to abnormal fat redistribution characterized by an enlarged belly, a lump on the back of the neck ("buffalo hump"), thinning of the face, arms, or legs.  In most cases this would be also accompanied by elevated cholesterol levels, elevated triglyceride levels (a fatty component of the blood), and perhaps a tendency to develop diabetes.  The first symptoms of diabetes are increased thirst and increased urination.

Interactions
This refers to the way that darunavir affects other medications and how other medications affect darunavir.

Make sure that you tell your healthcare provider about all of your medications including over-the-counter ones. 

Some medications probably should NOT be taken at all with darunavir:

Certain antihistamines: terfenadine (Seldane), astemizole (Hismanal)
Drugs to increase esophagus and stomach movement: cisapride
Drugs to regulate heart rhythm: flecainide (Tambocor), propafenone (Rhythmol, Rhythmol SR), amiodarone, quinidine, bepridil
Ergot derivatives for migraine headaches: dihydroergotamine (D.H.E. 45), ergonovine, ergotamine, methylergonovine (Methergine)
Drugs to treat mental health problems (Tourette's syndrome): pimozide (Orap)
Sedatives/sleeping pills: midazolam (Versed), triazolam (Halcion)
All statins (drugs to decrease cholesterol) other than atorvastatin (Lipitor), pravastatin (Pravachol)
Natural remedies: St John's wort, garlic capsules
Tuberculosis treatment: rifampin (Rifadin, Rimactane, Rifamate)

Certain drugs should probably be used only very cautiously:

Antacids that contain aluminum and/or magnesium: Maalox, Mylanta, and many others - always stagger (separate) dose away from darunavir/ritonavir by at least 2 hours
Oral diabetic medicines [hypoglycemics]: glimepiride, glipizide, glyburide, pioglitazone, repaglinide, tolbutamide - the interaction is unknown and therefore monitor for effectiveness carefully
Calcium channel blockers: diltiazem, felodipine, nicardipine, nisoldipine, verapamil
Antidepressant: desipramine [monitor the blood level and decrease the dose of desipramine], fluoxetine, paroxetine, sertraline
Certain HIV treatment medications: didanosine (Videx EC): separate Videx EC from darunavir by at least 2 hours
Drugs to prevent seizures: phenytoin (Dilantin)
All erectile dysfunction drugs: sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra)
Drugs to prevent rejection of transplanted organs or bone marrow: cyclosporine (Neoral, Sandimmune), tacrolimus (FK506, Prograf), sirolimus (Rapamune)
Drugs to treat mycobacteria or TB-like infections: Rifabutin (Mycobutin) [decrease rifabutin to 150 mg every other day]
Pain medication: methadone (Dolophine, Methadose), meperidine (Demerol) [avoid higher dosages and long-term use]
Oral contraceptive pills (another form of contraception should be used in addition).
Statin drugs: atorvastatin (Lipitor) [start with lowest possible dose]
Certain antibiotics: clarithromycin (Biaxin) [reduce dose of Biaxin if your kidney function is less than 1/3 of normal]
Antifungals: ketoconazole (Nizoral), itraconazole (Sporanox), voriconazole (Vfend)
Blood thinning medications: warfarin (Coumadin)

Report to you healthcare provider or go to an Emergency Room if you have severe side effects, skin rash, increasing side effects, shortness of breath, uncontrollable diarrhea, back pain, groin pain, fever, weakness, jaundice (eyes and skin turn yellow,) muscle pain, nausea and vomiting so that you cannot hold down your food and liquids.
You can download this handout in PDF format by clicking HERE.

4.11.2007