Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Ziagen. If you are concerned about side effects, discuss the risks and benefits of Ziagen with your doctor.

The following side effects have been reported by at least 1% of people taking Ziagen. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• Diarrhea (without other symptoms)
• fatigue
• Fever (without other symptoms)
• hair loss
• headache (without other symptoms)
• joint and muscle pain (without other symptoms)
• lack of energy
• loss of appetite
• nausea (without other symptoms)
• skin rash (without other symptoms)
• trouble sleeping
• upper abdominal pain (without other symptoms)
• vomiting (without other symptoms)

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood,  bleeding gums, cuts that don’t stop bleeding)
• signs of Depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of infection (e.g., fever or chills, sore throat, cough)
• symptoms of liver problems (nausea, vomiting, abdominal pain, weakness, diarrhea)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of bleeding in the stomach (e.g., bloody, black, or tarry stools, spitting up of blood, vomiting blood or material that looks like coffee grounds)
• signs of a severe skin reaction, e.g.:
• a rash combined with fever or discomfort
• a rash covering a large area of the body
• a rash that spreads quickly
• blistering
• peeling
• signs of pancreatitis, e.g.:
• abdominal pain on the upper left side
• back pain
• chills
• fever
• nausea
• rapid heartbeat
• swollen abdomen
• signs of lactic acidosis, e.g.:
• abdominal pain
• dizziness
• increased breathing rate
• nausea
• rapid heart rate
• unusual tiredness
• vomiting
• symptoms of allergic hypersensitivity reaction, e.g., :
• fever, rash
• nausea, vomiting, diarrhea, or abdominal pain
• severe tiredness, achiness, or generally feeling ill
• sore throat, shortness of breath, or cough

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Ziagen.

Oral Solution

Each mL of clear-to-opalescent, yellowish, strawberry-banana-flavoured liquid, contains abacavir sulfate equivalent to 20 mg of abacavir. Nonmedicinal ingredients: artificial strawberry and banana flavours, citric acid (anhydrous), hydrochloric acid, methylparaben, propylene glycol, propylparaben, saccharin sodium, sodium citrate (dihydrate), sodium hydroxide, and sorbitol solution.

Tablets

Each yellow, biconvex, capsule-shaped, film-coated tablet, scored and imprinted with "GX 623" on both sides, contains 300 mg of abacavir. Nonmedicinal ingredients: colloidal silicon dioxide, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polysorbate 80, sodium starch glycolate, titanium dioxide, triacetin, and yellow iron oxide.

Do not take abacavir - lamivudine if you:

• are allergic to abacavir, lamivudine, or any ingredients of the medication
• have had a hypersensitivity reaction to abacavir or any medication containing abacavir
• have reduced liver function
• have a genetic variation known as HLA-B*5701

There may be an interaction between abacavir - lamivudine and any of the following:

• alcohol
• co-trimoxazole (sulfamethoxazole/trimethoprim)
• emtricitabine
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• Methadone
• Orlistat
• other medications that contain abacavir or lamivudine
• retinoid medications (e.g., Isotretinoin)
• sorbitol
• Trimethoprim

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Ziagen. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Ziagen.

Heart Attack: Ziagen may increase your risk of heart attack. If you have heart problems, smoke, have high blood pressure or have Diabetes, discuss with your doctor how Ziagen may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Ziagen, and whether any special monitoring is needed.

Hepatitis B: If you have hepatitis B, your condition may worsen or recur if you stop taking Ziagen. Do not stop taking Ziagen unless recommended by your doctor. If your doctor recommends that you stop taking Ziagen, they will monitor you for several months after stopping treatment.

Hypersensitivity reactions: Ziagen can cause serious and sometimes fatal, hypersensitivity reactions. If you experience any of the following sets of symptoms, stop taking Ziagen and contact your doctor immediately:

• fever
• headache
• rash
• nausea, vomiting, diarrhea, or abdominal pain
• severe tiredness, achiness, or generally feeling ill
• sore throat, shortness of breath, or cough

These reactions usually occur within 6 weeks of starting Ziagen, but may occur at any time. If you have previously had an allergic reaction to abacavir or a medication that contains abacavir, you should not take Ziagen.

Immune reconstitution inflammatory syndrome: Ziagen may cause immune reconstitution inflammatory syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medication and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms (such as pneumonia, herpes, or Tuberculosis). Report any new symptoms to your doctor as soon as possible.

Kidney function: Kidney Disease or reduced kidney function may cause lamivudine to build up in the body, causing side effects. If you have reduced kidney function, discuss with your doctor how Ziagen may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Ziagen, and whether any special monitoring is needed. People with severely reduced kidney function should not take Ziagen.

Lactic acidosis and enlarged fatty liver: Lamivudine can cause a rare but serious condition called lactic acidosis (build-up of lactic acid in the blood) together with an enlarged liver. This tends to occur more often in women, especially if they are overweight. If you experience any of the following symptoms, call your doctor immediately:

• abdominal pain, swelling, or bloating
• diarrhea
• fatigue
• feeling unwell
• nausea
• shortness of breath
• vomiting
• weakness
• weight loss

Your doctor will monitor your liver function periodically by ordering laboratory tests.

Liver function: Liver disease or reduced liver function may cause abacavir to build up in the body, causing side effects. If you have reduced liver function or liver disease, discuss with your doctor how Ziagen may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Ziagen, and whether any special monitoring is needed.

Pancreatitis (inflammation of the pancreas): Abacavir - lamivudine may cause or worsen pancreatitis. If you have a history of or are at risk for developing pancreatitis, you should be closely monitored by your doctor while taking Ziagen. If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Red blood cells: Pure red cell aplasia is a rare bone marrow disorder in which there is a reduction in red blood cells produced by the bone marrow. Symptoms include pallor, weakness, shortness of breath, heart palpitations, and decreased blood pressure. If you experience any of these symptoms contact your doctor immediately.

Stopping the medication: If you stop taking Ziagen, your HIV infection could get worse. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first.

Pregnancy: Ziagen should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Ziagen, contact your doctor immediately.

Breast-feeding: Lamivudine and abacavir pass into breast milk. Women who have HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection.

Children: Ziagen may be used by children less than 18 years of age who weigh more than 25 kg. Although both abacavir and lamivudine have been used to treat HIV for children, the doses of the ingredients in Ziagen cannot be adjusted and may not be appropriate for people who weigh less than 25 kg.

Seniors:  People over the age of 65 years may be more at risk of side effects from Ziagen.