How does it work?

Reyataz capsules contain the active ingredient atazanavir, whichis a type of medicine called a protease inhibitor. It is used in the treatmentof HIV (human immunodeficiency virus) infection.

AIDS (acquired immune deficiency syndrome) is caused byinfection with HIV. This virus invades cells of the immune system, particularlythe white blood cells known as CD4 T-helper lymphocytes. These cells normallywork to activate other cells in the immune system to fight infection. Since HIVkills CD4 T-helper cells, over time the body becomes less able to fight thevirus or subsequent infections.

Once the virus has invaded a CD4 T-cell it multiplies, and newcopies of the virus are released to infect more CD4 cells. Certain chemicalsproduced by HIV, called enzymes, play an important role in this multiplication.One of these enzymes, protease, has an essential involvement in assembling thenew copies of the virus. Atazanavir works by stopping the protease enzyme fromworking. This means that new copies of the virus that are produced are faultyand cannot infect more CD4 cells.

There is no cure for HIV, but atazanavir is one of a number ofmedications that lowers the amount of virus in the body (viral load) and slowsthe progression of the disease from HIV to AIDS.

Atazanavir is usually used together with another anti-HIVmedicine calledritonavir(Norvir). A low-dose of ritonavir increases the amount of atazanavir inthe bood and is used to boost the effect of the atazanavir, rather than to haveany effect on the virus itself. This combination is used in conjunction withother anti-HIV drugs that attack the HIV virus in different ways. This helpsprevent the virus becoming resistant to the medicine.

What is it used for?

• HIV infection.

Warning!

• The HIV virus is very good at becoming resistant to anti-HIV medicines. For this reason it is very important that you carefully follow your doctor's instructions for taking your anti-HIV medicines, in order to maintain effective levels of the medicines in your blood. If the blood levels drop, the virus will be given more chance to replicate and develop resistance to the drugs. Skipping even a few doses increases the risk of treatment failure, so you should try to ensure that you take all your doses at the correct time, and that you visit your doctor for repeat prescriptions before you run out.
• Treatment of HIV infection with anti-HIV medicines such as this one does not reduce the risk of transmitting the virus to other people through sexual contact or blood contamination. You should continue to use condoms to prevent transmitting the virus to your sexual partner.
• Combination antiretroviral therapy has been associated with a redistribution of body fat (lipodystrophy) in people with HIV. The long-term consequences of this are currently unknown, however your doctor may wish to monitor your body fat, and the levels of lipids (eg cholesterol) and sugar (glucose) in your blood, and may prescribe additional medicines for any lipid disorders that occur during treatment with this medicine. Contact your doctor if you notice any changes in your body fat during treatment with your HIV medicines.
• Some people being treated with combination antiretroviral therapy may develop a bone condition called osteonecrosis. This condition is caused by loss of blood supply to a bone, causing death of the bone tissue. The risk of the condition is thought to be increased by corticosteroid use, alcohol consumption, severe immunosuppression, higher body mass index (BMI), advanced HIV disease and long-term use of antiretroviral medicines. If you notice any joint stiffness, aches and pains (especially of the hip, knee and shoulder) or difficulty in movement while using this medicine, you should tell your doctor so this can be investigated.
• You will need to have regular blood tests to monitor your liver function while you are taking this medicine. This is especially important if you already have any problems with your liver, in particular chronic hepatitis B or C. Symptoms that may suggest a liver problem include persistent nausea and vomiting, abdominal pain, or the development of jaundice (a yellow colouring to the skin and the whites of the eyes). Consult your doctor if you experience any of these symptoms.

Use with caution in

• The blood clotting disorder haemophilia (this medicine may increase the risk of bleeding in haemophilia).
• Diabetes.
• Decreased liver function.
• History of hepatitis.
• Problems with the transfer of electrical signals within the heart (heart conduction defects).
• Abnormal heart beat seen on a heart monitoring trace (ECG) as a 'prolonged QT interval'.
• Slow heart rate (bradycardia).
• Disturbance in the levels of salts (electrolytes) such as potassium or magnesium in the blood.

Not to be used in

• Moderate to severely decreased liver function.
• People undergoing haemodialysis for kidney failure.
• Rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption (Reyataz capsules contain lactose).

This medicine should not be used if you are allergic to any ofits ingredients. Please inform your doctor or pharmacist if you have previouslyexperienced such an allergy.

If you feel you have experienced an allergic reaction, stopusing this medicine and inform your doctor or pharmacistimmediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy orbreastfeeding. However, other medicines may be safely used in pregnancy orbreastfeeding providing the benefits to the mother outweigh the risks to theunborn baby. Always inform your doctor if you are pregnant or planning apregnancy, before using any medicine.

• The safety of this medicine in pregnancy has not been established. It should therefore be used with caution during pregnancy, and only if the benefits to the mother outweigh any risks to the foetus. Seek medical advice from your doctor.
• It is recommended that women infected with the HIV virus must not breastfeed their infants under any circumstances, in order to avoid transmission of the virus to the baby. Seek medical advice from your doctor.

Label warnings

• Take this medication with or after food.

Side effects

Medicines and their possible side effects can affect individualpeople in different ways. The following are some of the side effects that areknown to be associated with this medicine. Just because a side effect is statedhere does not mean that all people using this medicine will experience that orany side effect.

Common (affect between 1 in 10 and 1 in 100 people)

• Headache.
• Yellowing of the skin and eyes (jaundice).
• Disturbances of the gut such as nausea, vomiting, diarrhoea or abdominal pain.
• Skin reactions such as rash and itch.
• Fatigue.
• Loss or gain of body fat and other changes in fat distribution (see warning section above).

Uncommon (affect between 1 in 100 and 1 in 1000 people)

• Fainting (syncope).
• Disorder of the peripheral nerves causing numbness or tingling in the hands or feet (peripheral neuropathy).
• Loss of memory (amnesia).
• Dizziness.
• Sleepiness (somnolence).
• Taste changes.
• Mouth ulcers.
• Inflammation of the liver (hepatitis).
• Inflammation of the pancreas (pancreatitis).
• Kidney problems such as kidney failure or kidney stones.
• Awareness of your heartbeat (palpitations).
• Pain in the muscles and joints.
• Weakness or loss of strength (asthenia).
• Appetite and weight changes.
• Chest pain.
• Abnormal dreams.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

• Abnormal gait.
• Enlargement of liver and spleen.
• Disorder of the muscles (myopathy).

Frequency not known

• Raised levels of cholesterol or sugar in the blood.
• Diabetes.
• A type of irregular heart beat (Torsades de Pointes).
• Gallbbadder disorders.

The side effects listed above may not include all of the sideeffects reported by the medicine's manufacturer.

For more information about any other possible risks associatedwith this medicine, please read the information provided with the medicine orconsult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicinesyou are taking, including those bought without a prescription and herbalmedicines, before you start treatment with this medicine. Likewise, alwayscheck with your doctor or pharmacist before taking any other medicines duringtreatment with this one so that they can ensure that thecombination is safe.

When atazanavir is used in combination with ritonavir(Norvir)ritonavir, yourdoctor or pharmacist will also check whether any of your medicines interactwithritonavir.

Atazanavir should not be taken in combination with any of thefollowing medicines:

• astemizole
• bepridil
• cisapride
• ergot alkaloids, particularly ergotamine, dihydroergotamine
• midazolam taken by mouth
• pimozide
• proton pump inhibitors, eg omeprazole, lansoprazole
• quinidine
• rifampicin
• terfenadine
• the herbal remedy St John's wort (Hypericum perforatum)
• triazolam.

Your doctor may need to adjust the doses of other anti-HIVmedicines you are already taking when this medicine is added to yourtreatment.

If you are taking didanosine as part of youranti-HIV therapy, it is recommended that you take yourdidanosine two hours after taking this medicine with food.This is because didanosine must be taken on an empty stomach.

This medicine is not recommended for use in combination with thefollowing anti-HIV medicines:

• indinavir
• nevirapine.

It is recommended that the atazanavir plus ritonavir regimen isnot used in combination with other protease inhibitors.

The following medicines may reduce the absorption of atazanavirfrom the gut:

• antacids (this medicine should be taken two hours before, or one hour after, any medicines that contain an antacid)
• H₂ antagonists, eg ranitidine, famotidine (this medicine should be taken two hours before, or at least 10 hours after, any medicines that contain an H₂ antagonist)
• proton pump inhibitors, eg omeprazole, lansoprazole (proton pump inhibitors should not be taken with this medicine).

There may be an increased risk of abnormal heart rhythms ifatazanavir is taken in combination with any of the followingmedicines:

• medicines to treat abnormal heart rhythms, eg amiodarone, procainamide, sotalol
• diltiazem
• verapamil
• certain antipsychotics, eg thioridazine
• certain antimalarials, eg chloroquine.

This medicine may increase the risk of side effects from theanti-cancer medicine irinotecan.

This medicine may increase the blood levels of statins used totreat high cholesterol levels. Simvastatin andlovastatin are not recommended for use in combination with thismedicine. Atorvastatin should be used withcaution.

This medicine may also increase the blood levels of thefollowing medicines, and this may increase the risk of their side effects. Yourdoctor may therefore need to reduce the dose of these medicines:

• ciclosporin
• tacrolimus
• sirolimus
• clarithromycin
• rifabutin
• sildenafil
• oral contraceptives.

Atazanavir may reduce the effectiveness of hormonalcontraceptives containing ethinylestradiol. For this reason,women taking Reyataz who need contraception should be prescribed hormonalcontraceptives that contain a total of at least 30 micrograms ofethinylestradiol (oestrogen). Alternatively, other methods ofcontraception could be used. A barrier method of contraception, such ascondoms, will prevent pregnancy, as well as preventingtransmission of the HIV virus. Discuss this with your doctor.

Atazanavir plus ritonavir may increase the blood level of thecorticosteroids fluticasone and budesonidetaken by inhaler or nasal spray. This could increase the risk of systemic sideeffects of these steroids, such as Cushing's syndrome, or decreased productionof natural steroids by the adrenal glands. For this reason, the use of thesecorticosteroids in combination with atazanavir and ritonavir is notrecommended, unless the benefits are thought to outweigh the potential risks.

The antifungal medicines itraconazoleand ketoconazole may increase the blood level of atazanavirand should be used with caution in combination with this medicine.

This medicine may alter the anti-blood-clotting effect of theanticoagulant medicine warfarin. If you are taking warfarinyour blood clotting time (INR) should be monitored when you start treatmentwith this medicine.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK thatcontain atazanavir as the active ingredient.