Abacavir or any medicinal product containing abacavir, MUST NEVER be restarted in patients who have stopped therapy due to HSR.
Rechallenge can result in a more rapid and severe reaction, which can be fatal. Rechallenge is contraindicated.
Restarting abacavir following HSR results in a prompt return of symptoms within hours and this recurrence is usually more severe than on initial presentation, and may include life-threatening hypotension and death.
If abacavir therapy is stopped for reasons other than suspected HSR:
- Screening for carriage of the HLA B*5701 allele is recommended prior to re-initiation of abacavir in patients of unknown HLA-B*5701 status who have previously tolerated abacavir. Re-initiation of abacavir in such patients who test positive for the HLA-B*5701 allele is contraindicated.
- Rarely, patients who have stopped abacavir for reasons other than symptoms of HSR have also experienced life-threatening reactions within hours of re- initiating abacavir therapy. Restarting abacavir in such patients must be done in a setting where medical assistance is readily available.