Name: Abacavir

How should I take abacavir?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Abacavir comes with a Medication Guide and a Warning Card that lists the symptoms of an allergic reaction. Read this information carefully and carry the Warning Card with you at all times so you will know what symptoms to watch for.

Abacavir can be taken with or without food.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

While using abacavir, you may need frequent blood tests.

Use abacavir regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

HIV/AIDS is usually treated with a combination of drugs. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice. Every person with HIV or AIDS should remain under the care of a doctor.

Store at room temperature away from moisture and heat.

You may store the oral solution (liquid) in the refrigerator but do not let it freeze.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

Abacavir side effects

Stop using abacavir and call your doctor at once if you have symptoms of an allergic reaction from two or more of these specific side effect groups:

  • Group 1 - fever;

  • Group 2 - rash;

  • Group 3 - nausea, vomiting, diarrhea, stomach pain;

  • Group 4 - general ill feeling, extreme tiredness, body aches;

  • Group 5 - shortness of breath, cough, sore throat.

Once you have had an allergic reaction to abacavir, you must never use it again. If you stop taking abacavir for any reason, talk to your doctor before you start taking the medication again.

Abacavir can cause other serious side effects that may not be signs of an allergic reaction. Call your doctor at once if you have:

  • the first sign of any skin rash, no matter how mild;

  • chest pain or pressure, pain spreading to your jaw or shoulder;

  • severe pain in your upper stomach spreading to your back, nausea and vomiting, fast heart rate; or

  • liver problems--nausea, swelling around your midsection, upper stomach pain, unusual tiredness, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Early symptoms of lactic acidosis may get worse over time and this condition can be fatal. Get emergency medical help if you have even mild symptoms: muscle pain or weakness, numb or cold feeling in your arms and legs, trouble breathing, stomach pain, nausea with vomiting, fast or uneven heart rate, dizziness, or feeling very weak or tired.

Abacavir may increase your risk of certain infections or autoimmune disorders by changing the way your immune system works. Symptoms may occur weeks or months after you start treatment with abacavir. Tell your doctor if you have:

  • signs of a new infection--fever, night sweats, swollen glands, mouth sores, diarrhea, stomach pain, weight loss;

  • chest pain (especially when you breathe), dry cough, wheezing, feeling short of breath;

  • cold sores, sores on your genital or anal area;

  • rapid heart rate, feeling anxious or irritable, weakness or prickly feeling, problems with balance or eye movement;

  • trouble speaking or swallowing, severe lower back pain, loss of bladder or bowel control; or

  • swelling in your neck or throat (enlarged thyroid), menstrual changes, impotence, loss of interest in sex.

Common side effects may include:

  • sleep problems, strange dreams;

  • headache, tiredness, fever, chills, general ill feeling;

  • nausea or vomiting;

  • changes in the shape or location of body fat (especially in your arms, legs, face, neck, breasts, and waist); or

  • (in children) stuffy nose, sneezing, sore throat, ear pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Oral:

Ziagen: 20 mg/mL (240 mL) [contains methylparaben, propylene glycol, propylparaben, saccharin sodium; strawberry-banana flavor]

Tablet, Oral:

Ziagen: 300 mg [scored]

Generic: 300 mg

ALERT U.S. Boxed Warning

Hypersensitivity reactions:

Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with abacavir.

Patients who carry the HLA-B*5701 allele are at a higher risk of a hypersensitivity reaction to abacavir; although, hypersensitivity reactions have occurred in patients who do not carry HLA-B*5701 allele.

Abacavir is contraindicated in patients with a prior hypersensitivity reaction to abacavir and in HLA-B*5701–positive patients. All patients should be screened for the HLA-B*5701 allele prior to initiating therapy with abacavir or reinitiation of therapy with abacavir, unless patients have a previously documented HLA-B*5701 allele assessment. Discontinue abacavir immediately if a hypersensitivity reaction is suspected, regardless of HLA-B*5701 status and even when other diagnoses are possible.

Following a hypersensitivity reaction to abacavir, never restart abacavir or any abacavir-containing product because more severe symptoms including death, can occur within hours. Similar severe reactions have also occurred rarely following the reintroduction of abacavir-containing products in patients who have no history of abacavir hypersensitivity.

Lactic acidosis and severe hepatomegaly with steatosis:

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues and other antiretrovirals. Discontinue abacavir if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur.

Other uses for this medicine

Abacavir is also used in combination with other antiviral medications to prevent HIV infection in people who have been exposed to it. Talk to your doctor about the possible risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Dosing & Uses

Dosage Forms & Strengths

oral solution

  • 20mg/mL


  • 300mg

HIV Infection

300 mg PO q12hr, OR

600 mg PO qDay in combination with other antiretroviral agents

Dosage Modifications

Renal impairment: No dosage adjustment required

Hepatic impairment

  • Mild (Child-Pugh 5-6): Reduce dose to 200 mg q12hr (use oral solution)
  • Moderate-to severe: Contraindicated

Dosage Forms & Strengths

oral solution

  • 20mg/mL


  • 300mg

HIV Infection

Indicated for treatment of HIV infection in combination with other antiretroviral agents

Neonates/Infants <3 months: Safety and efficacy not established

Oral solution

  • ≥3 months: 8 mg/kg PO q12hr or 16 mg/kg/day; not to exceed 600 mg/day in combination with other antiretroviral agents 


  • Available as a scored tablet; if unable to reliably swallow tablets, prescribe the oral solution
  • ≥14 kg to <20 kg: 150 mg PO q12hr, OR 300 mg qDay
  • ≥20 to <25 kg: 150 mg AM and 300 mg PM, OR 450 mg qDay
  • ≥25 kg: 300 mg PO q12hr, OR 600 mg PO qDay in combination with other antiretroviral agents

Dosing Considerations

Once daily dosing: NIH pediatric HIV guidelines (March, 2016) recommend initiation of therapy with once-daily dosing in children who can be treated with the tablet formulation

Twice daily dosing: Use twice daily dosing in infants and young children initiating therapy with liquid formulations; consider switching to once-daily dosing after 6 months when viral load is undetectable and CD4 cell count is stable

Patient Handout

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Uses of Abacavir

Abacavir is a prescription medicine used to treat human immunodeficiency virus (HIV) infection. Abacavir is always used with other anti-HIV medicines. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Side Effects of Abacavir

Abacavir can cause the following serious side effects:

  • Serious allergic reaction that can cause death. (See "Drug Precautions".)
  • Lactic acidosis with liver enlargement (hepatomegaly) that can cause death. (See "Drug Precautions".)
  • Changes in immune system. When you start taking HIV medicines, your immune system may get stronger and could begin to fight infections that have been hidden in your body, such as pneumonia, herpes virus, or tuberculosis. If you have new symptoms after starting your HIV medicines, be sure to tell your doctor.
  • Changes in body fat. These changes have happened in patients taking antiretroviral medicines like abacavir. The changes may include an increased amount of fat in the upper back and neck (“buffalo hump”), breast, and around the back, chest, and stomach area. Loss of fat from the legs, arms, and face may also happen. The cause and long-term health effects of these conditions are not known.

Some HIV medicines including abacavir may increase your risk of heart attack. If you have heart problems, smoke, or suffer from diseases that increase your risk of heart disease such as high blood pressure, high cholesterol, or diabetes, tell your doctor.

The most common side effects of abacavir include nausea, vomiting, tiredness, headache, diarrhea, trouble sleeping, fever and chills, and loss of appetite. Most of these side effects did not cause people to stop taking abacavir.

This list of side effects is not complete. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Abacavir Dosage

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

  • the condition being treated
  • other medical conditions you have
  • other medications you are taking
  • how you respond to this medication
  • your weight
  • your age

Adult Patients

The recommended oral (by mouth) dose of abacavir for adults is 600 mg daily, administered as either 300 mg twice daily or 600 mg once daily, in combination with other antiretroviral agents.

Pediatric Patients

The recommended dose of Ziagen (abacavir) (oral solution) in patients aged 3 months and older is 8 mg per kg twice daily or 16 mg per kg once-daily (up to a maximum of 600 mg daily) in combination with other antiretroviral agents.

Pediatric patients weighing greater than or equal to 14 kg, Ziagen tablet can be prescribed and taken. 


Other Requirements

  • Store abacavir at room temperature, between 68° to 77°F (20° to 25°C). Do not freeze abacavir.
  • Keep abacavir and all medicines out of the reach of children.

Usual Adult Dose for Nonoccupational Exposure

US CDC recommendations: 300 mg orally twice a day or 600 mg orally once a day
Duration of therapy: 28 days

-Recommended as part of alternative regimens (NNRTI-based, protease inhibitor-based, or triple NRTI) for nonoccupational postexposure prophylaxis of HIV infection
-Prophylaxis should be started as soon as possible, within 72 hours of exposure.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Occupational Exposure

US Public Health Service working group recommendations: 300 mg orally twice a day or 600 mg orally once a day
Duration of therapy: 28 days, if tolerated

-Only with expert consultation, as part of an alternative regimen for use as HIV postexposure prophylaxis
-Prophylaxis should be started as soon as possible, preferably within hours after exposure.
-The optimal duration of prophylaxis is unknown and may differ based on institution protocol.
-Current guidelines should be consulted for additional information.

Other Comments

Administration advice:
-Use in combination with other antiretroviral agents.
-May administer without regard to food
-If patient is unable to reliably swallow a tablet, use the oral solution.
-Consult the manufacturer product information regarding missed doses.

Storage requirements:
-Oral solution: Store at 20C to 25C (68F to 77F); may refrigerate; do not freeze.
-Tablets: Store at 20C to 25C (68F to 77F).

-Screening for HLA-B*5701 allele recommended before starting this drug.
-Before starting this drug, medical history should be reviewed for prior exposure to any abacavir-containing product (to prevent reintroduction in patient with history of abacavir hypersensitivity).

Patient advice:
-Always read the Medication Guide and Warning Card (with information about abacavir hypersensitivity reaction) dispensed with each new and refill prescription; carry the Warning Card.
-Contact physician immediately if signs/symptoms of hypersensitivity develop; do not restart this or any other abacavir-containing product after a hypersensitivity reaction.
-If this drug is stopped for any reason besides hypersensitivity, do not restart it (or any other abacavir-containing product) without consulting physician; medical care must be readily accessible.

Abacavir Identification

Substance Name


CAS Registry Number


Drug Class

Antiinfective Agents

Anti-HIV Agents

Antiviral Agents

Anti-Retroviral Agents

Reverse Transcriptase Inhibitors