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Abacavir / lamivudine Side Effects

Medically reviewed by Last updated on Jan 27, 2024.

Applies to abacavir / lamivudine: oral tablet.


Oral route (Tablet)

Hypersensitivity Reactions:Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with abacavir, a component of the abacavir and lamivudine combination. 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 the HLA-B*5701 allele.The abacavir and lamivudine combination 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 and lamivudine or reinitiation of therapy with abacavir and lamivudine, unless patients have a previously documented HLA-B*5701 allele assessment. Discontinue abacavir and lamivudine combination 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 and lamivudine combination, never restart abacavir and lamivudine or any other 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.Exacerbations of Hepatitis B:Severe acute exacerbations of hepatitis B have been reported in patients who are co-infected with hepatitis B virus (HBV) and human immunodeficiency virus (HIV-1) and have discontinued lamivudine, which is a component of abacavir and lamivudine combination. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who discontinue abacavir and lamivudine and are co-infected with HIV-1 and HBV. If appropriate, initiation of anti-hepatitis B therapy may be warranted.

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:

More common

Incidence not known

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:

More common

Incidence not known

For Healthcare Professionals

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


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]


Abacavir and lamivudine:

-Common (1% to 10%): Drug hypersensitivity

-Postmarketing reports: Sensitization reactions (including anaphylaxis)


-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)


-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]


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


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


-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]


Abacavir and lamivudine:

-Common (1% to 10%): Nausea, diarrhea, abdominal pain/gastritis, abnormal amylase

-Postmarketing reports: Stomatitis


-Common (1% to 10%): Nausea, vomiting, diarrhea

-Postmarketing reports: Pancreatitis


-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]


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]

Abacavir and lamivudine:

-Common (1% to 10%): Rash

-Postmarketing reports: Alopecia, erythema multiforme, Stevens-Johnson syndrome, urticaria


-Frequency not reported: Sweet's syndrome

-Postmarketing reports: Rash without systemic symptoms, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis


-Common (1% to 10%): Rash

-Rare (less than 0.1%): Angioedema

-Frequency not reported: Pruritus, urticaria

-Postmarketing reports: Alopecia[Ref]


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


-Frequency not reported: Anemia, neutropenia, agranulocytosis


-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


-Common (1% to 10%): Headache


-Common (1% to 10%): Headache

-Postmarketing reports: Paresthesia, peripheral neuropathy[Ref]


Abacavir and lamivudine:

-Common (1% to 10%): Fatigue/malaise, pyrexia

-Postmarketing reports: Weakness


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


-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]


Abacavir and lamivudine:

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


-Common (1% to 10%): Insomnia[Ref]


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


-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


-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]


Abacavir and lamivudine:

-Uncommon (0.1% to 1%): Abnormal creatine phosphokinase (CPK)

-Postmarketing reports: Muscle weakness, CPK elevation, rhabdomyolysis


-Frequency not reported: Elevated CPK


-Postmarketing reports: Arthralgia, muscle disorders, rhabdomyolysis

Combination antiretroviral therapy:

-Frequency not reported: Osteonecrosis[Ref]



-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.


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)


Abacavir and lamivudine:

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


Abacavir and lamivudine:

-Postmarketing reports: Abnormal breath sounds/wheezing


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


1. Product Information. Epzicom (abacavir-lamivudine). GlaxoSmithKline. 2004.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

4. Loeliger AE, Steel H, McGuirk S, Powell WS, Hetherington SV. The abacavir hypersensitivity reaction and interruptions in therapy. Aids. 2001;15:1325.

5. Toerner JG, Cvetkovich T. Kawasaki-like Syndrome: Abacavir Hypersensitivity? Clin Infect Dis. 2002;34:131-2.

6. Hetherington S, McGuirk S, Powell G, et al. Hypersensitivity reactions during therapy with the nucleoside reverse transcriptase inhibitor abacavir. Clin Ther. 2001;23:1603-14.

7. Cutrell AG, Hernandez JE, Fleming JW, et al. Updated clinical risk factor analysis of suspected hypersensitivity reactions to abacavir. Ann Pharmacother. 2004;38:2171-2.

8. Eron J Jr, Yeni P, Gathe J Jr, et al. The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial. Lancet. 2006;368:476-82.

9. Del Giudice P, Vandenbos F, Perrin C, Bernard E, Marq L, Dellamonica P. Sweet's syndrome following abacavir therapy. J Am Acad Dermatol. 2004;51:474-5.

10. Sankatsing SU, Prins JM. Agranulocytosis and fever seven weeks after starting abacavir. AIDS. 2001;15:2464-5.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.