Background: New dosing regimens for ceftriaxone 4 g/24 hours and ceftazidime 3 g/12 hours are convenient for patients receiving OPAT. To date, these have not been clinically validated.

Aim: To assess the tolerability, toxicity and effectiveness of once daily ceftriaxone (4 g) and 12 hourly ceftazidime regimens (3 g twice a day) in the OPAT setting.

Patients and methods: From April 2018 until March 2023; demographic, clinical, microbiological and outcome data were collected on all adult patients discharged to a community-based OPAT team in East London.

Results: There were 487 OPAT episodes. Fifty-three (10.9%) patients received ceftriaxone 4 g once a day and 20 (4.1%) ceftazidime 3 g twice a day. In the ceftriaxone group, the commonest conditions treated were orthopaedic, neurosurgical or diabetic foot infections. OPAT was used to expedite the discharge of 45 (84.9%) patients, the remainder were admission avoidance episodes. The commonest isolate causing infection was MSSA 23 (43.4%). There were no tolerability or toxicity episodes recorded. All patients were cured and bed days saved were 1266.In the smaller twice-daily ceftazidime cohort, seven (35%) patients were treated for necrotizing otitis externa, six (30%) for bronchiectasis and six (30%) for urinary tract infections. The commonest cause of infection was P. aeruginosa, 18 (90%). One case of nephrotoxicity was recorded. All patients were cured and bed days saved were 896.

Conclusions: Regimens of ceftriaxone 4 g once a day and ceftazidime 3 g twice a day were well tolerated and highly effective. If widely adopted, these regimens will save OPAT and nursing time and enable more patients to be treated.

Wareham D, Melzer M. Clinical outcomes in OPAT patients treated with ceftriaxone 4 g and ceftazidime 6 g extended interval dosing regimens. JAC Antimicrob Resist. 2024 May 30;6(3):dlae079. doi: 10.1093/jacamr/dlae079. PMID: 38817948; PMCID: PMC11138961.