3.1[12] prescribed and dispensed in Wales were extracted from CASPA.net for the period June 2004 to December 2010 (12 months before and 66 months after OTC ophthalmic chloramphenicol availability). OTC sales data were obtained from IMS Health and included four established proprietary brands of both chloramphenicol eye drops and ointment (Brochlor, Golden Eye Antibiotic, Galpharm Vision, Optrex Infected Eyes), together with one proprietary brand (Tubilux) and one own-brand of eye drops. As at December

2010, there were two further proprietary brands of chloramphenicol eye drops available as P medicines in the UK[25] but data for these products were unavailable and thus not included in the analysis. Ophthalmic chloramphenicol preparations licensed as POMs, such as Minims eye drops, were excluded from the OTC sales analysis. The OTC sales

data obtained were available from June 2005 to December 2010 (66 months) and ITF2357 research buy represented the supply of ophthalmic chloramphenicol preparations from wholesalers into 614/708 (87%) NHS-contracted community pharmacies in Wales. Data for the remaining 94 NHS-contracted pharmacies and eight pharmacies without NHS contract CHIR-99021 were obtained direct from the pharmacy chain concerned (Company A) for the period January 2008 to December 2010 (36 months). OTC sales of chloramphenicol eye drops from Company A between June 2005 and December 2007 (30 months) and ointment between July and December 2007 (6 months) were estimated using linear regression. The line of best fit generated from the model was extrapolated backwards based on available cumulative sales data. The OTC sales from Company A (estimated and actual) were combined with IMS Health sales data to give the total quantity of OTC ophthalmic chloramphenicol sold in Wales from June 2005 to December 2010. The total number of items supplied on prescription or sold OTC are presented as the 12 month totals for the eye drops, from June to May, and for the ointment, from

July to June, to allow the comparison before and after their respective availability OTC. The correlation coefficient (r) for prescription items supplied and OTC sales of combined chloramphenicol eye drops and ointment was calculated NADPH-cytochrome-c2 reductase using Spearman’s rank correlation, based on actual prescribing and OTC sales data between January 2008 and December 2010. All data analysis and statistics were performed using PASW version 18 (SPSS, Chicago, IL, USA). The linear regression model generated cumulative sales equations for eye drops (R2 = 0.998, P < 0.0001) and eye ointment (R2 = 0.995, P < 0.0001) for Company A and estimated cumulative sales for the respective periods when no data were available (data not shown). The total cumulative quantities of ophthalmic chloramphenicol sold OTC (IMS Health + Company A; actual and estimated OTC sales) are shown in Figure 1. The supply of chloramphenicol eye drops from 2004–2005 to 2009–2010 is shown in Figure 2.