Subcutaneously administered antibiotics: a review (addendum)

Addendum to: Journal of Antimicrobial Chemotherapy, Volume 78, Issue 1, January 2023, Pages 1–7, https://doi.org/10.1093/jac/dkac383. Published online 14 November 2022. We recently published the article ‘Subcutaneously administered antibiotics: a review’,1 and would like to add two other articles in this review. The first described subcutaneous (SC) ertapenem use from a large Australian outpatient parenteral antimicrobial therapy (OPAT) study, and provided comparative efficacy with the IV route of administration.2 In this study, chronic renal impairment was more common in the SC group. Adverse events were uncommon and successful outcomes were not different between the groups. The second demonstrates favourable pharmacokinetics (PK) as well as tolerability and safety of the SC approach for benzathine penicillin.3 In this study, 15 healthy males participated in a randomized crossover study to receive benzathine penicillin G by either the SC or IM routes, with a 10 week washout period. Lower peak and higher trough penicillin concentrations resulted following SC injection. Simulations demonstrated that SC infusion of higher doses of benzathine penicillin G could provide therapeutic penicillin concentrations for 3 months. A single high dose of benzathine penicillin G via the SC route would therefore attain pharmaco-equivalence with three doses of 2.4 MIU benzathine penicillin G given via deep IM injection every week, currently recommended for the treatment of late latent syphilis.4 It would represent a major step forward for syphilis management by allowing a single healthcare attendance, thereby avoiding incomplete adherence and associated healthcare costs. However, this hypothesis needs further confirmation.