Abacavir

Name: Abacavir

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Abacavir dosing information

Usual Adult Dose for HIV Infection:

300 mg orally twice a day or 600 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

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

Comments:
-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

Comments:
-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.

Usual Pediatric Dose for HIV Infection:

3 months or older:
Oral solution: 8 mg/kg orally twice a day or 16 mg/kg orally once a day
Maximum dose: 600 mg/day

Tablets:
14 to less than 20 kg: 150 mg orally twice a day or 300 mg orally once a day
20 to less than 25 kg: 150 mg orally in the morning and 300 mg in the evening, or 450 mg orally once a day
25 kg or more: 300 mg orally twice a day or 600 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

What other drugs will affect abacavir?

Tell your doctor about all your current medicines and any you start or stop using, especially:

  • methadone; or

  • any other HIV medicines.

This list is not complete. Other drugs may interact with abacavir, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Precautions While Using abacavir

It is very important that your doctor check the progress of you or your child at regular visits to make sure that abacavir is working properly. Blood tests may be needed to check for unwanted effects.

Do not use abacavir if you are also using other medicines containing abacavir (eg, Epzicom®, Triumeq®, Trizivir®).

abacavir may cause severe allergic reactions in some patients. These reactions usually occur within 6 weeks after the medicine is started but may occur at any time. If untreated, it can lead to severe low blood pressure and even death. Check with your doctor immediately if you or your child notice sudden fever, skin rash, diarrhea, nausea, stomach pain, vomiting, or a feeling of unusual tiredness or illness, cough, trouble breathing, or sore throat.

When you begin taking abacavir, you or your child will be given a warning card which describes symptoms of severe allergic reactions that may be caused by abacavir. The warning card also provides information about how to treat these allergic reactions. For your safety, you should carry the warning card with you at all times.

Do not stop using abacavir unless your doctor tells you to do so. If you stop using abacavir for any reason, do not start taking it again without talking first to your doctor.

If you must stop using abacavir because of an allergic reaction, you should never use the medicine again. Return the unused medicine to your doctor or pharmacist. A worse reaction, possibly even death, can occur if you use the medicine again. Tell your doctor right away if you or your child have ever taken abacavir, especially if you have experienced an allergic reaction to it in the past.

Two rare but serious reactions to abacavir are lactic acidosis (too much acid in the blood) and liver toxicity. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child have more than one of these symptoms: stomach discomfort or cramping, dark urine, decreased appetite, diarrhea, general feeling of discomfort, light-colored stools, muscle cramping or pain, nausea, unusual tiredness or weakness, trouble breathing, vomiting, or yellow eyes or skin.

When you start taking HIV medicines, your immune system may get stronger. If you or your child have certain infections that are hidden in your body, such as pneumonia or tuberculosis, you may notice new symptoms when your body tries to fight them. Tell your doctor right away if you or your child notice any changes in health.

abacavir may cause you to have excess body fat. Tell your doctor if you or your child notice changes in your body shape, such as an increased amount of fat in the upper back and neck, or around the chest and stomach area, or a loss of fat from the legs, arms, and face.

abacavir may increase your risk of having a heart attack. This is more likely to occur if you smoke or already have heart disease, high blood pressure, or high cholesterol or fats in the blood. Call your doctor right away if you have chest pain or discomfort, nausea, pain or discomfort in the arms, jaw, back or neck, trouble breathing, sweating, or vomiting. These could be symptoms of a heart attack.

abacavir will not keep you from giving HIV to your partner during sex. Make sure you understand and practice safe sex, such as using latex condoms, even if your partner also has HIV. Do not share needles, toothbrushes, and razor blades with anyone.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Index Terms

  • Abacavir Sulfate
  • ABC

Dosing Pediatric

HIV-1 infection, treatment: Oral:

Infants ≥3 months, Children, and Adolescents: Note: Efficacy of once daily dosing has only been demonstrated in patients who transitioned from twice daily dosing after 36 weeks of treatment. Some experts recommend avoiding once daily therapy for infants and young children receiving oral solution until viral load has been undetectable and CD4 have been stable for more than 6 months (HHS [pediatric 2016]).

Weight-directed dosing: Oral solution: 16 mg/kg/day in 1 or 2 divided doses (maximum: 600 mg/day). Note: Weight-band dosing may be used in certain patients weighing ≥14 kg; especially rapid growing younger children (HHS [pediatric] 2016)

Weight-band directed dosing for patients ≥14 kg: Tablets (scored 300 mg tablets), oral solution:

14 to <20 kg: 300 mg once daily or 150 mg twice daily

≥20 to <25 kg: 450 mg once daily or 150 mg in the morning and 300 mg in the evening

≥25 kg: 600 mg once daily or 300 mg twice daily

Storage

Store at 20°C to 25°C (68°F to 77°F). Oral solution may be refrigerated; do not freeze.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience vomiting, headache, nausea, diarrhea, lack of appetite, loss of strength and energy, insomnia, or nightmares. Have patient report immediately to prescriber signs of allergic reaction with organ failure (fever, rash, fatigue, flu-like signs, nausea, vomiting, diarrhea, abdominal pain, pharyngitis, cough, or difficulty breathing), signs of lactic acidosis (fast breathing, tachycardia, abnormal heartbeat, vomiting, fatigue, shortness of breath, severe loss of strength and energy, severe dizziness, feeling cold, or muscle pain or cramps), signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), signs of kidney problems (urinary retention, hematuria, change in amount of urine passed, or weight gain), depression, angina, severe dizziness, passing out, mouth sores, muscle pain, muscle weakness, burning or numbness feeling, edema, change in body fat, enlarged lymph nodes, or signs of infection (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

What are the side effects of abacavir?

The most common side effects are:

  • nausea,
  • vomiting,
  • headache,
  • fatigue,
  • allergic reactions,
  • diarrhea,
  • loss of appetite,
  • difficulty sleeping,
  • muscle pain,
  • increased triglyceride levels,
  • rash,
  • anxiety,
  • depression, and
  • fever.

The most serious side effects are severe allergic reactions, pancreatitis, liver failure, and metabolic disturbance (lactic acidosis). Symptoms of an allergic reaction include skin rash, fever, weakness, swelling and difficulty breathing. Abacavir must be stopped as soon an allergic reaction is suspected, and it should not be restarted after an allergic reaction.

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Reviewed on 6/10/2015 References Reference: FDA Prescribing Information

Warnings

Black Box Warnings

Hypersensitivity Reactions

  • Severe and sometimes fatal hypersensitivity reactions (discontinue immediately if hypersensitivity reaction suspected); Never restart after suspected hypersensitivity reaction because more severe symptoms can occur within hours and may include life-threatening hypotension and death
  • Reintroduction of abacavir or any other abacavir-containing product, even in patients who have no identified history or unrecognized symptoms of hypersensitivity to abacavir therapy, can result (within hours) in serious or fatal hypersensitivity reactions
  • Hypersensitivity reaction to this drug is a multiorgan clinical syndrome usually characterized by a sign or symptom in 2 or more of the following groups: (1) fever, (2) rash, (3) gastrointestinal (including nausea, vomiting, diarrhea, or abdominal pain, (4) constitutional (eg, generalized malaise, fatigue, achiness), and (5) respiratory (eg, pharyngitis, dyspnea, cough)
  • Hypersensitivity reactions & HLA-B*5701 allele (section 2) HLA-B*5701 allele carriers at high risk for hypersensitivity reaction, Prior to initiating therapy, screen for the HLA-B*5701 allele; this approach decreases risk of hypersensitivity reaction
  • Screening also recommended prior to reinitiation in patients of unknown HLA-B*5701 status who have previously tolerated abacavir therapy
  • HLA-B*5701 allele-negative patients may develop hypersensitivity reaction, although frequency significantly less than in HLA-B*5701-positive patients
  • Regardless of HLA-B*5701 status, permanently discontinue if hypersensitivity cannot be ruled out, even when other diagnoses are possible

Lactic Acidosis and Hepatomegaly

  • Lactic acidosis and hepatomegaly with steatosis (including fatal cases) reported with use of nucleoside analogues alone or in combination

Contraindications

Hypersensitivity;

Presence of HLA-B*5701 allele

Moderate or severe hepatic impairment

Cautions

All NRTIs: Risk of potentially fatal lactic acidosis & severe hepatomegaly with steatosis when used alone or in combination with other antiretrovirals

Risk of immune reconstitution syndrome; may result in occurrence of inflammatory response to indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders, including polymyositis and graves disease, later in therapy, which may require further evaluation and treatment

Increased risk of serious or fatal hypersensitivity reactions in patients w/ human leukocyte antigen allele, HLA-B*5701; do not restart abacavir following hypersensitive reaction without regard of HLA-B-5701, may cause hypotension, death

May cause redistribution of fat that may result in cushingoid appearance

Use has been associated with increased risk of myocardial infarction in observational studies but not in a meta-analysis of 26 randomized trials; use with caution in patients with risks for coronary heart disease and minimizing modifiable risk factors, including smoking, hypertension, and hyperlipidemia, prior to use

Abacavir Precautions

The most important information you should know about abacavir:

  • Serious Allergic Reaction to Abacavir. Abacavir is also contained in Epzicom and Trizivir. Patients taking abacavir may have a serious allergic reaction (hypersensitivity reaction) that can cause death. Your risk of this allergic reaction is much higher if you have a gene variation called HLA-B*5701 than if you do not. Your doctor can determine with a blood test if you have this gene variation. If you get a symptom from 2 or more of the following groups while taking abacavir, call your doctor right away to determine if you should stop taking this medicine.

Symptoms:

Group 1: Fever

Group 2: Rash

Group 3: Nausea, vomiting, diarrhea, abdominal (stomach area) pain 

Group 4: Generally ill feeling, extreme tiredness, or achiness

Group 5: Shortness of breath, cough, sore throat

A list of these symptoms is on the Warning Card your pharmacist gives you. Carry this Warning Card with you.

If you stop abacavir because of an allergic reaction, NEVER take abacavir or any other abacavir-containing medicine (Epzicom and Trizivir) again. If you take abacavir or any other abacavir-containing medicine again after you have had an allergic reaction, WITHIN HOURS you may get life-threatening symptoms that may include very low blood pressure or death.

If you stop abacavir for any other reason, even for a few days and you are not allergic to abacavir, talk with your doctor before taking it again. Taking abacavir again can cause a serious allergic or life-threatening reaction, even if you never had an allergic reaction to it before. If your doctor tells you that you can take abacavir again, start taking it when you are around medical help or people who can call a doctor if you need one.

  • Lactic Acidosis. Some human immunodeficiency virus (HIV) medicines, including abacavir, can cause a rare but serious condition called lactic acidosis with liver enlargement (hepatomegaly). Nausea and tiredness that don't get better may be symptoms of lactic acidosis. In some cases this condition can cause death. Women, overweight people, and people who have taken HIV medicines like abacavir for a long time have a higher chance of getting lactic acidosis and liver enlargement. Lactic acidosis is a medical emergency and must be treated in the hospital.

Abacavir can have other serious side effects. Be sure to read the section entitled "Side Effects".

Do not take abacavir if you:

  • have ever had a serious allergic reaction (a hypersensitivity reaction) to abacavir or any other medicine that has abacavir as one of its ingredients (Epzicom and Trizivir).
  • have a liver that does not function properly.

Inform MD

Before starting abacavir, tell your doctor about all of your medical conditions, including if you:

  • have been tested and know whether or not you have a particular gene variation called HLA-B*5701.
  • are pregnant or planning to become pregnant. It is not known if abacavir will harm your unborn child. You and your doctor will need to decide if abacavir is right for you. If you use abacavir while you are pregnant, talk to your doctor about how you can be on the Antiviral Pregnancy Registry for abacavir.
  • are breastfeeding. It is not known if abacavir can be passed to your baby in your breast milk and whether it could harm your baby. Also, mothers with HIV should not breastfeed because HIV can be passed to the baby in the breast milk.
  • have liver problems.
  • 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 about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements.

Abacavir Usage

  • Take abacavir by mouth exactly as your doctor prescribes it. Your doctor will tell you the right dose to take. The usual doses are 1 tablet twice a day or 2 tablets once a day. Do not skip doses.
  • Children aged 3 months and older can also take abacavir. The child's healthcare professional will decide the right dose and formulation based on the child's weight. The dose should not exceed the recommended adult dose.
  • You can take abacavir with or without food.
  • If you miss a dose of abacavir, take the missed dose right away. Then, take the next dose at the usual time.
  • Do not let your abacavir run out.
  • Starting abacavir again can cause a serious allergic or life-threatening reaction, even if you never had an allergic reaction to it before. If you run out of abacavir even for a few days, you must ask your doctor if you can start abacavir again. If your doctor tells you that you can take abacavir again, start taking it when you are around medical help or people who can call a doctor if you need one.
  • If you stop your anti-HIV drugs, even for a short time, the amount of virus in your blood may increase and the virus may become harder to treat.
  • If you take too much abacavir, call your doctor or poison control center right away.

What you should avoid while taking abacavir:

  • Do not take Epzicom (abacavir sulfate and lamivudine) or Trizivir (abacavir sulfate, lamivudine, and zidovudine) while taking abacavir.

Avoid doing things that can spread HIV infection, as abacavir does not stop you from passing the HIV infection to others.

  • Do not share needles or other injection equipment.
  • Do not share personal items that can have blood or body fluids on them, like toothbrushes and razor blades.
  • Do not have any kind of sex without protection. Always practice safe sex by using a latex or polyurethane condom or other barrier method to lower the chance of sexual contact with semen, vaginal secretions, or blood.
  • Do not breastfeed. It is not known if abacavir can be passed to your baby in your breast milk and whether it could harm your baby. Also, mothers with HIV should not breastfeed because HIV can be passed to the baby in the breast milk.

In Summary

Commonly reported side effects of abacavir include: arthralgia, cough, fatigue, lethargy, myalgia, pruritus, vomiting, chills, and malaise. Other side effects include: hypersensitivity, pharyngitis, and tachypnea. See below for a comprehensive list of adverse effects.

Usual Adult Dose for HIV Infection

300 mg orally twice a day or 600 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

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