Abacavir / Lamivudine Side Effects

Medically reviewed by Drugs.com. Last updated on Apr 11, 2025.

Applies to abacavir / lamivudine: oral tablet.

Precautions

It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly. Blood tests may be needed to check for unwanted effects.

This medicine may cause severe allergic reactions (including multi-organ failure) in some patients. This reaction usually occurs 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 right away if you have sudden fever, skin rash, diarrhea, nausea, stomach pain, vomiting, or a feeling of unusual tiredness or illness, cough, trouble breathing, sore throat, lightheadedness, dizziness, or yellow skin or eyes.

When you begin using this medicine, you will be given a Warning Card which describes symptoms of severe allergic reactions that may be caused by abacavir and lamivudine combination. 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.

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 have ever taken abacavir, especially if you have experienced an allergic reaction to it in the past.

Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity, which includes an enlarged liver. 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 have more than one of these symptoms: abdominal or 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.

Your immune system may get stronger when you start using HIV medicines. Tell your doctor right away if you notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia or tuberculosis, or may result in a flare-up of a hidden autoimmune disorder such as Graves disease, polymyositis, or Guillain-Barré syndrome.

This medicine may cause you to have excess body fat. Tell your doctor if you 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.

This medicine may increase your risk of having a heart attack. This is more likely to occur if you already have heart disease, high blood pressure, high cholesterol or fats in the blood, or if you smoke.

This medicine 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.

Serious side effects

Along with its needed effects, abacavir / lamivudine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking abacavir / lamivudine:

Other side effects

Some side effects of abacavir / lamivudine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to abacavir / lamivudine: oral tablet, oral tablet dispersible.

General adverse events

In 1 study, once- or twice-daily abacavir was used in combination with lamivudine and efavirenz. Patients receiving once-daily abacavir had a significantly higher incidence of severe drug hypersensitivity reactions and severe diarrhea than patients on the twice-daily regimen.

Many of the side effects listed occurred commonly in patients with abacavir hypersensitivity (e.g., nausea, vomiting, diarrhea, fever, lethargy, rash).^[Ref]

Hypersensitivity

Abacavir and lamivudine:

• Common (1% to 10%): Drug hypersensitivity
• Postmarketing reports: Sensitization reactions (including anaphylaxis)

Abacavir:

• Common (1% to 10%): Hypersensitivity reactions (including fever, rash [maculopapular, urticarial], nausea, vomiting, diarrhea, abdominal pain, pharyngitis, generalized malaise, fatigue, achiness, dyspnea, cough, lethargy, headache, myalgia, arthralgia, myolysis, edema, abnormal chest x-ray findings [mainly localized infiltrates], paresthesia, anaphylaxis, hepatitis, liver failure, renal failure, hypotension, sore throat, adult respiratory distress syndrome, respiratory failure, death, lymphadenopathy, mucous membrane lesions [conjunctivitis, mouth ulcerations], erythema multiforme, elevated liver function tests, elevated creatine phosphokinase, elevated creatinine, lymphopenia)

Lamivudine:

• Frequency not reported: Anaphylactoid reactions^[Ref]

Serious and sometimes fatal hypersensitivity reactions have been reported with abacavir. Such reactions have included multi-organ failure and anaphylaxis and usually occurred within the first 6 weeks of abacavir therapy (median onset: 9 to 11 days); however, abacavir hypersensitivity reactions have occurred any time during therapy.

Patients with the human leukocyte antigen subtype B*5701 (HLA-B*5701) allele are at higher risk of abacavir hypersensitivity reactions; however, such reactions have occurred in patients without the HLA-B*5701 allele. Abacavir hypersensitivity was reported in about 8% of patients in 9 clinical trials with abacavir-containing products where patients were not screened for the HLA-B*5701 allele; incidence of suspected abacavir hypersensitivity reactions was 1% in clinical trials where HLA-B*5701 carriers were excluded.

Abacavir hypersensitivity reactions have been characterized by at least 2 of the following key signs/symptoms: (1) fever; (2) rash; (3) gastrointestinal symptoms (including nausea, vomiting, diarrhea, abdominal pain); (4) constitutional symptoms (including generalized malaise, fatigue, achiness); (5) respiratory symptoms (including dyspnea, cough, pharyngitis). Almost all reactions have included fever and/or rash (usually maculopapular or urticarial); however, reactions also reported without fever or rash. Signs/symptoms reported in at least 10% of patients with hypersensitivity reaction have included rash, nausea, vomiting, diarrhea, abdominal pain, dyspnea, cough, fever, fatigue/lethargy, malaise, headache, elevated liver function tests, and myalgia. Other signs/symptoms of hypersensitivity have included mouth ulceration, sore throat, adult respiratory distress syndrome, respiratory failure, edema, lymphadenopathy, hypotension, conjunctivitis, anaphylaxis, paresthesia, lymphopenia, hepatitis, liver failure, myolysis, arthralgia, elevated creatine phosphokinase, elevated creatinine, renal failure, abnormal chest x-ray findings (mainly infiltrates, which were localized), and death.

Symptoms of abacavir hypersensitivity reaction worsened with continued therapy and generally resolved when abacavir was discontinued. Restarting abacavir after a hypersensitivity reaction has resulted in more severe symptoms within hours and included life-threatening hypotension and death. Rarely, life-threatening reactions have occurred within hours after restarting abacavir in patients who stopped it for reasons other than symptoms of hypersensitivity (or who stopped it with only 1 key symptom of hypersensitivity).^[Ref]

Hepatic

Abacavir and lamivudine:

• Common (1% to 10%): Elevated ALT, elevated AST
• Uncommon (0.1% to 1%): Abnormal bilirubin
• Frequency not reported: Severe hepatomegaly with steatosis
• Postmarketing reports: Hepatic steatosis, posttreatment exacerbation of hepatitis B

Abacavir:

• Frequency not reported: Liver function test abnormalities, elevated GGT

Lamivudine:

• Uncommon (0.1% to 1%): Transient elevations in liver enzymes (AST, ALT)
• Rare (less than 0.1%): Hepatitis
• Frequency not reported: Elevated bilirubin, elevated hepatic enzymes, hepatic decompensation, severe acute exacerbations of hepatitis^[Ref]

Lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) have been reported with the use of nucleoside analogs.

Elevated GGT was observed in the expanded access program for abacavir.

Severe acute exacerbations of hepatitis have been reported in patients with hepatitis B after discontinuation of lamivudine.^[Ref]

Gastrointestinal

Abacavir and lamivudine:

• Common (1% to 10%): Nausea, diarrhea, abdominal pain/gastritis, abnormal amylase
• Postmarketing reports: Stomatitis

Abacavir:

• Common (1% to 10%): Nausea, vomiting, diarrhea
• Postmarketing reports: Pancreatitis

Lamivudine:

• Common (1% to 10%): Nausea, vomiting, abdominal pain/cramps, diarrhea
• Frequency not reported: Elevated lipase
• Postmarketing reports: Elevated serum amylase, pancreatitis^[Ref]

Pancreatitis was observed in the expanded access program for abacavir.^[Ref]

Dermatologic

Abacavir and lamivudine:

• Common (1% to 10%): Rash
• Postmarketing reports: Alopecia, erythema multiforme, Stevens-Johnson syndrome, urticaria

Abacavir:

• Frequency not reported: Sweet's syndrome
• Postmarketing reports: Rash without systemic symptoms, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis

Lamivudine:

• Common (1% to 10%): Rash
• Rare (less than 0.1%): Angioedema
• Frequency not reported: Pruritus, urticaria
• Postmarketing reports: Alopecia^[Ref]

Suspected Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported in patients using abacavir primarily in combination with agents known to be associated with SJS and TEN, respectively.

Cases of erythema multiforme, SJS, or TEN have been reported very rarely when abacavir hypersensitivity could not be ruled out.^[Ref]

Hematologic

Abacavir and lamivudine:

• Common (1% to 10%): Abnormal absolute neutrophils
• Uncommon (0.1% to 1%): Abnormal hemoglobin, abnormal platelets, abnormal WBC
• Postmarketing reports: Aplastic anemia, anemia (including pure red cell aplasia and severe anemias progressing on therapy), lymphadenopathy, splenomegaly

Abacavir:

• Frequency not reported: Anemia, neutropenia, agranulocytosis

Lamivudine:

• Uncommon (0.1% to 1%): Thrombocytopenia, neutropenia, anemia
• Postmarketing reports: Pure red cell aplasia^[Ref]

Agranulocytosis has been reported after the addition of abacavir to a multi-drug regimen.

Occasionally, neutropenia and anemia reported with lamivudine were severe.^[Ref]

Nervous system

Abacavir and lamivudine:

• Common (1% to 10%): Headache/migraine, dizziness/vertigo
• Postmarketing reports: Peripheral neuropathy, paresthesia, seizures

Abacavir:

• Common (1% to 10%): Headache

Lamivudine:

• Common (1% to 10%): Headache
• Postmarketing reports: Paresthesia, peripheral neuropathy^[Ref]

Other

Abacavir and lamivudine:

• Common (1% to 10%): Fatigue/malaise, pyrexia
• Postmarketing reports: Weakness

Abacavir:

• Common (1% to 10%): Fever, lethargy, fatigue

Lamivudine:

• Common (1% to 10%): Fatigue, malaise, fever
• Frequency not reported: Drug-resistant hepatitis B virus (HBV)

Antiretroviral therapy:

• Frequency not reported: Increased weight, increased blood lipid levels

Combination antiretroviral therapy:

• Frequency not reported: Fat loss, fat gain^[Ref]

The emergence of lamivudine-resistant HBV has been reported in HIV-1/HBV-coinfected patients using lamivudine-containing antiretroviral regimens.^[Ref]

Psychiatric

Abacavir and lamivudine:

• Common (1% to 10%): Insomnia, depression/depressed mood, abnormal dreams, anxiety

Lamivudine:

• Common (1% to 10%): Insomnia^[Ref]

Metabolic

Abacavir and lamivudine:

• Common (1% to 10%): Abnormal triglycerides
• Uncommon (0.1% to 1%): Abnormal alkaline phosphatase, abnormal glucose, abnormal sodium
• Frequency not reported: Lactic acidosis
• Postmarketing reports: Hyperglycemia, redistribution/accumulation of body fat

Abacavir:

• Common (1% to 10%): Anorexia
• Very rare (less than 0.01%): Lactic acidosis
• Frequency not reported: Elevated blood glucose, elevated triglycerides
• Postmarketing reports: Hyperlactatemia, lactic acidosis

Lamivudine:

• Very rare (less than 0.01%): Lactic acidosis
• Postmarketing reports: Hyperlactatemia, lactic acidosis

Antiretroviral therapy:

• Frequency not reported: Increased glucose level^[Ref]

Lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) have been reported with the use of nucleoside analogs.^[Ref]

Musculoskeletal

Abacavir and lamivudine:

• Uncommon (0.1% to 1%): Abnormal creatine phosphokinase (CPK)
• Postmarketing reports: Muscle weakness, CPK elevation, rhabdomyolysis

Abacavir:

• Frequency not reported: Elevated CPK

Lamivudine:

• Postmarketing reports: Arthralgia, muscle disorders, rhabdomyolysis

Combination antiretroviral therapy:

• Frequency not reported: Osteonecrosis^[Ref]

Cardiovascular

Abacavir:

• Postmarketing reports: Myocardial infarction (MI)

Several prospective, observational, epidemiological studies reported an association with the use of abacavir and the risk of MI. Meta-analysis of randomized, controlled clinical trials showed no excess risk of MI in abacavir-treated patients as compared with control subjects. Overall, available data from observational studies and controlled clinical trials showed inconsistency; evidence for causal relationship between abacavir and risk of MI was inconclusive.

Immunologic

• Frequency not reported: Immune reconstitution/reactivation syndrome, autoimmune disorders in the setting of immune reconstitution (e.g., Graves' disease, polymyositis, Guillain-Barre syndrome, autoimmune hepatitis)

Renal

Abacavir and lamivudine:

• Uncommon (0.1% to 1%): Abnormal creatinine^[Ref]

Respiratory

Abacavir and lamivudine:

• Postmarketing reports: Abnormal breath sounds/wheezing

Lamivudine:

• Common (1% to 10%): Cough, nasal symptoms^[Ref]

See also:

Further information

Abacavir/lamivudine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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