Topical chloramphenicol usage in Australia pre‐ and post‐rescheduling as a non‐prescription medication

Abstract

Topical chloramphenicol became a Schedule 3 (Pharmacist Only Medication, not requiring a written prescription, for ophthalmic use only) medication in Australia on 1 May 2010. The Australian Therapeutic Goods Administration has approved topical chloramphenicol for the treatment of bacterial conjunctivitis (BC) only (without medical supervision), meaning that pharmacists can only independently supply topical chloramphenicol for BC. A 47.8% increase in total chloramphenicol use was reported to have occurred following similar rescheduling in the UK in 2005. Here, we provide evidence for an even larger rise in chloramphenicol dispensing in Australia as a result of this scheduling change. The incidence of BC in Australia is not well documented. We estimated the incidence of BC in Australia by conducting a literature review of over 540 published papers. Using the largest estimate available where the diagnosis of BC was at least predominantly by an ophthalmologist, we estimated the incidence of BC in Australia to be 13.5 cases/1000 head of population/year (13.5/1000/y). To determine the usage rate for BC alone, we subtracted any ocular procedures (Tables 1 and 2) where chloramphenicol might be used from the total units per annum. Chloramphenicol ointment is reportedly used to prevent surgical site infections. Before rescheduling, chloramphenicol was predominantly prescribed by medical practitioners, so we therefore conservatively assumed that all pre-rescheduling ointment was for non-ocular use. The mean pre-rescheduling ointment usage (23.9/1000, Table 1) was multiplied by the Australian population to derive the adjusted units in Table 2, allowing for population growth in surgical procedures. Corneal abrasions are not accorded an item number under the Medicare Benefits Scheme, but chloramphenicol may be prescribed prophylactically for these presentations. We estimated the number of presentations for corneal abrasions using data from Tovell and McKenna (Table 2.3), who reported that abrasions to the cornea and injury to the conjunctiva comprised 2.8% of eye injury cases admitted to hospitals in Australia, whilst foreign bodies in the cornea