Never Rechallenge

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.

NP-GBL-HVX-WCNT-220048 November 2022

Report an adverse event

Adverse events should be reported. Reporting forms and information can be found at or search for MHRA Yellowcard in the Google Play or Apple App store. Adverse events should also be reported to GlaxoSmithKline on 0800 221441.

If you are from outside the UK, you can report adverse events to GSK/ViiV by selecting your region and market, here.