Abacavir / lamivudine Side Effects

Not all side effects for abacavir / lamivudine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to abacavir / lamivudine: oral tablet

In addition to its needed effects, some unwanted effects may be caused by abacavir / lamivudine. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking abacavir / lamivudine:

More common
  • Hypersensitivity reaction, including abdominal or stomach pain; cough; diarrhea; fever; headache; nausea; numbness or tingling of the face, feet, or hands; pain in the joints; pain in the muscles; shortness of breath; skin rash; sore throat; swelling of the feet or lower legs; unusual feeling of discomfort or illness; unusual tiredness or weakness; or vomiting
Incidence not known
  • Blistering, peeling, or loosening of the skin
  • bloating
  • burning, numbness, tingling, or painful sensations
  • chest pain
  • chills
  • constipation
  • convulsions
  • dark urine
  • decreased appetite
  • diarrhea
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • fast, shallow breathing
  • feeling of fullness
  • general feeling of discomfort
  • hives or welts
  • indigestion
  • itching
  • light-colored stools
  • loss of appetite
  • loss of bladder control
  • muscle cramping
  • muscle spasm or jerking of all extremities
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pale skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • red, irritated eyes
  • redness of the skin
  • red skin lesions, often with a purple center
  • sleepiness
  • sores, ulcers, or white spots on the lips or in the mouth
  • sudden loss of consciousness
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • tightness in the chest
  • troubled breathing with exertion
  • unsteadiness or awkwardness
  • unusual bleeding or bruising
  • upper right abdominal or stomach pain
  • weakness in the arms, hands, legs, or feet
  • wheezing
  • yellow eyes and skin

Some of the side effects that can occur with abacavir / lamivudine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Abnormal dreams
  • burning feeling in the chest or stomach
  • fear
  • feeling of constant movement of self or surroundings
  • lightheadedness
  • nervousness
  • sensation of spinning
  • severe and throbbing headache
  • sleeplessness
  • stomach upset
  • tenderness in the stomach area
  • trouble with sleeping
  • unable to sleep
Incidence not known
  • Abnormal breathing sounds
  • blurred vision
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • dry mouth
  • flushed, dry skin
  • fruit-like breath odor
  • gaining weight around your neck, upper back, breast, face, or waist
  • hair loss
  • increased hunger
  • increased thirst
  • increased urination
  • muscle weakness
  • sweating
  • swelling or inflammation of the mouth
  • thinning of the hair
  • unexplained weight loss

For Healthcare Professionals

Applies to abacavir / lamivudine: oral tablet


Hypersensitivity side effects associated with abacavir have included serious and sometimes fatal hypersensitivity reactions. Frequently observed signs and symptoms have included, but were not limited to, fever, skin rash (maculopapular, urticarial, or variable appearance), nausea, vomiting, diarrhea, abdominal pain, pharyngitis, malaise, fatigue, achiness, dyspnea, and cough. Other symptoms of abacavir hypersensitivity have included lethargy, myolysis, edema, abnormal chest X-ray (infiltrates), paresthesia, anaphylaxis, liver failure, renal failure, hypotension, adult respiratory distress syndrome, respiratory failure, death, lymphadenopathy, mucous membrane lesions (conjunctivitis and stomatitis), elevated liver function tests, elevated creatine phosphokinase, elevated creatinine, and lymphopenia. Lamivudine has been associated with angioedema, urticaria, and anaphylactoid reactions. Sensitization reactions (including anaphylaxis) and urticaria have been reported during postmarketing experience with abacavir and lamivudine.[Ref]

Abacavir hypersensitivity is a clinical syndrome affecting multiple organs generally characterized by a sign or symptom in two or more of the following groups:
(1) Fever
(2) Rash
(3) Gastrointestinal (including nausea, vomiting, diarrhea, or abdominal pain)
(4) Constitutional (including generalized malaise, fatigue, or achiness)
(5) Respiratory (including dyspnea, cough, or pharyngitis)

A strong predictor of hypersensitivity reaction may be the presence of human leukocyte antigen subtype B*5701 (HLA-B*5701). Analyzing past studies, patients testing positive for the HLA-B*5701 allele had a greater risk (61% to about 70%) of developing hypersensitivity reactions with abacavir, while patients without the HLA-B*5701 allele had a low risk (less than 1% to 4%); therefore, screening for the HLA-B*5701 allele is recommended prior to starting abacavir treatment. Therapy with an abacavir-containing regimen is not recommended for HLA-B*5701-positive patients and should be considered only with close medical supervision under exceptional conditions where potential benefit outweighs the risk. Considerably less frequently, HLA-B*5701-negative patients may experience hypersensitivity reaction with abacavir.

Abacavir should be permanently discontinued as soon as a hypersensitivity reaction is suspected. Severe or fatal hypersensitivity reactions can also occur within hours after restarting abacavir in patients who have no identified history or unrecognized symptoms of this reaction.[Ref]


Hepatic side effects associated with abacavir have included liver function test abnormalities and elevated gamma-glutamyltransferase. Elevated hepatic enzymes, elevated bilirubin, and rare cases of hepatic decompensation have been reported with lamivudine. Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination with other antiretroviral agents. Lactic acidosis, hepatic steatosis, and posttreatment exacerbation of hepatitis B have been reported during postmarketing experience with abacavir and lamivudine.[Ref]

Hepatic decompensation, sometimes fatal, has been reported in patients coinfected with HIV-1 and hepatitis C virus. These patients were receiving combination antiretroviral therapy for HIV-1 and interferon alfa with or without ribavirin.

Severe acute exacerbations of hepatitis, including fatalities, have been reported in patients coinfected with hepatitis B virus and HIV-1 who have discontinued antihepatitis B therapy, including lamivudine. The causal relationship to stopping lamivudine treatment is unknown.[Ref]


Pancreatitis has been rarely reported in adults (less than 0.5%), but may be more common in pediatric patients (up to 15% in 2 limited studies) receiving lamivudine.[Ref]

Gastrointestinal side effects of at least moderate intensity have included nausea (up to 6%), diarrhea (up to 6%), and abdominal pain/gastritis (up to 5%) with abacavir / lamivudine/efavirenz therapy. Pancreatitis has been reported with abacavir and lamivudine. Stomatitis has been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Dermatologic side effects of at least moderate intensity have included rash (5%) with abacavir / lamivudine/efavirenz therapy. Sweet's syndrome has been reported with abacavir. Lamivudine has been associated with rash, pruritus, and alopecia. Erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported during postmarketing experience with abacavir (alone or in combination with other drugs). Alopecia, erythema multiforme, and Stevens-Johnson syndrome have been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Hematologic side effects associated with abacavir have included anemia, neutropenia, and agranulocytosis. Thrombocytopenia has been reported with lamivudine. Aplastic anemia, anemia (including pure red cell aplasia and severe anemias progressing on therapy), lymphadenopathy, and splenomegaly have been reported during postmarketing experience with abacavir and lamivudine.[Ref]

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

Nervous system

Nervous system side effects of at least moderate intensity have included insomnia (up to 9%), headache/migraine (up to 7%), and dizziness/vertigo (6%) with abacavir / lamivudine/efavirenz combination therapy. Peripheral neuropathy, paresthesia, and seizures have been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Other side effects of at least moderate intensity have included fatigue/malaise (up to 8%) and pyrexia (up to 5%) with abacavir / lamivudine/efavirenz therapy. Weakness has been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Psychiatric side effects of at least moderate intensity have included depression/depressed mood (7%), abnormal dreams (up to 5%), and anxiety (up to 5%) with abacavir / lamivudine/efavirenz therapy.[Ref]


Metabolic side effects associated with abacavir have included elevated blood glucose and triglycerides. Elevated amylase and lipase have been reported with lamivudine. Redistribution and/or accumulation of body fat including central obesity, dorsocervical fat enlargement, peripheral wasting, facial wasting, breast enlargement, and "cushingoid appearance" have been observed in patients taking antiretroviral agents; however, a causal relationship has not been established. Hyperglycemia and redistribution/accumulation of body fat have been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Musculoskeletal side effects associated with abacavir have included elevated creatine phosphokinase (CPK). Muscle weakness, CPK elevation, and rhabdomyolysis have been reported during postmarketing experience with abacavir and lamivudine.[Ref]


Cardiovascular side effects have included myocardial infarction during postmarketing experience with abacavir.

A study investigating the frequency of myocardial infarction (MI) in patients taking combination antiretroviral treatment showed an increased risk of MI with the use of abacavir within the previous 6 months; however, these results are not conclusive. The manufacturer reviewed its own clinical study databases and although the results of the analysis are inconclusive, they did not show an excess risk of MI. A meta-analysis conducted by the FDA showed no statistically significant difference in MI events between patients who received abacavir and those who did not.


Immunologic side effects have included immune reconstitution syndrome. Autoimmune disorders (e.g., Graves' disease, polymyositis, and Guillain-Barre syndrome) have been reported in the setting of immune reconstitution. The emergence of lamivudine-resistant hepatitis B virus (HBV) has been reported in HIV-1-infected patients who were treated with lamivudine-containing regimens in the presence of coinfection with HBV.


Respiratory side effects have included abnormal breath sounds/wheezing during postmarketing experience with abacavir and lamivudine.[Ref]


1. 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 368 (2006): 476-82

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

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

4. HHS Panel on Antiretroviral Guidelines for Adults and Adolescents – A Working Group of the Office of AIDS Research Advisory Council (OARAC). NIH. National Institutes of Health "Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. Available from: URL: http://aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf." ([2011 Oct 14]):

5. "Product Information. Epzicom (abacavir-lamivudine)." GlaxoSmithKline, Research Triangle Park, NC.

6. Piacenti FJ "An update and review of antiretroviral therapy." Pharmacotherapy 26 (2006): 1111-33

7. Toerner JG, Cvetkovich T "Kawasaki-like Syndrome: Abacavir Hypersensitivity?" Clin Infect Dis 34 (2002): 131-2

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

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

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

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