Hypersensitivity Reactions And Exacerbations Of Hepatitis B

Hypersensitivity Reactions

Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with abacavir, a component of abacavir and lamivudine. 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 [see Warnings and Precautions (5.1)].

Abacavir and lamivudine is contraindicated in patients with a prior hypersensitivity reaction to abacavir and in HLA‑B*5701-positive patients [see Contraindications (4), Warnings and Precautions (5.1)]. 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 immediately if a hypersensitivity reaction is suspected, regardless of HLA-B*5701 status and even when other diagnoses are possible [see Contraindications (4), Warnings and Precautions (5.1)].

Following a hypersensitivity reaction to abacavir and lamivudine, 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 [see Warnings and Precautions (5.1)].

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. 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 [see Warnings and Precautions (5.2)].