Aims Azithromycin is a macrolide antibiotic which has been used as prophylaxis against lower respiratory tract infections in individuals who are at increased risk. We noted that clinicians within paediatrics prescribe different prophylactic regimes, notably: 1. Azithromycin Monday, Wednesday, Friday every week 2. Azithromycin Friday, Saturday, Sunday alternate weekends. A literature search was performed to identify studies comparing these regimes. Formal inquiry with the pharmacy department was performed to investigate relative pharmacokinetic effects. A survey was carried out to investigate prophylactic azithromycin regimes used within paediatrics in the East of England.

Methods Advanced literature search in the databases Medline, EMBASE and Trip Database was performed. Formal inquiry was submitted to the pharmacy department by the lead paediatric pharmacist. A six-question survey was sent to a consultant at all remaining paediatric departments within the East of England. In the absence of a reply, the on-call paediatric registrar at that hospital was contacted and if possible the survey was completed over the telephone. Questions related to use of prophylactic azithromycin, dose, dosing regime, use of other prophylactic antibiotics and indications.

Results Literature search did not identify any published data comparing these two regimes of prophylactic azithromycin. Pharmacy inquiry did not reveal any advantages of one regime over the other. 14/17 (82%) of paediatric departments in the East of England region took part in the survey including all 3 tertiary centres. 100% of participating departments use prophylactic azithromycin. Three different dosing regimes were mentioned in replies: 1. Three times per week (usually Monday/Wednesday/Friday) 2. Friday-Sunday alternate weekends 3. Three doses over 48 hours every two weeks. The most commonly used regime was regime 1, used by 13/14 (93%) of departments. 64% of departments use regime 1 only and 29% reported use of regimes 1 and 2.

Conclusion Azithromycin is commonly used as a prophylactic antibiotic for children at risk of LRTIs within the East of England region and clinicians commonly use regimes 1 and 2. It is possible that these regimes have significantly different prophylactic effects and hence we suggest that it may be beneficial to investigate this formally in a randomised controlled trial.