Objectives To identify the rate of adverse events for ceftriaxone, ertapenem, daptomycin, teicoplanin, piperacillin/tazobactam and meropenem on an outpatient parenteral antibiotic (OPAT) service.

Method We identified all patients on our prospectively populated OPAT Access Database from 2009 to 2016. Duration on OPAT and the details of any documented antibiotic adverse/toxic events, were recorded.

Results Ertapenem was used most commonly at 356/961 (37%) specific antibiotic episode per all antibiotic episodes, followed jointly by both ceftriaxone 241/961 (25%), teicoplanin 237/961 (25%), with meropenem 59/961 (6%), piperacillin/tazobactam 42/961 (4%) and daptomycin 26/961 (3%). The total number of antibiotic adverse events for the six antibiotics being investigated was 48/961 (5%). Piperacillin/tazobactam has a significantly higher rate of adverse events compared with most of the other antibiotics studied (12/42; 29%) followed by daptomycin (3/26; 12%; p=0.1362), ceftriaxone (16/241; 7%; p=0.0001), meropenem (3/59; 5%; p=0.0015), teicoplanin (10/237; 4%; p=0.0001) and ertapenem (4/356; 1%; p=0.0001). Ertapenem has a significantly lower rate of toxicity compared with some of the other antibiotics investigated. When standardised per 1000 OPAT days, piperacillin/tazobactam continues to have a significantly higher rate of toxicity (8.3 episodes of antibiotic toxicity per 1000 OPAT days), with again ertapenem having a significant lower rate of toxicity (0.5) compared with some of the remaining antibiotics.

Conclusion While the overall number of adverse events directly attributable to the antibiotics examined was only 5%, it may be possible to optimise antibiotics to reduce this percentage.