The use of fixed dose drug combinations for glaucoma in clinical settings: a retrospective, observational, single-centre study

BACKGROUND The aim of study was to understand anti-glaucoma fixed dose drug combination use in real-world settings, focussing on drug selection, repeated prescription of the same active ingredient, and administration of fixed dose combinations, thus providing a reference for doctors during prescription and pharmacists during prescription review, ultimately educating patients on medication. METHODS A retrospective, observational, single-centre study was conducted. Outpatient prescriptions for anti-glaucoma eye drops from 01 January to 31 March 2021 were extracted. The prescriptions containing anti-glaucoma fixed dose combinations were analysed, and the rationale for each prescription was reviewed. RESULTS There were 10,947 ophthalmic patients with anti-glaucoma eye drop prescriptions in the study period. Of these, 4002 (36.5%) were prescribed anti-glaucoma fixed dose drug combinations. Approximately 80% of the patients were prescribed brinzolamide/timolol, while about 10% received prostaglandin analogues/timolol eye drops. Less than 40% of prescriptions were for monotherapy with fixed dose combinations. The most commonly duplicated drug class was β-receptor antagonists. An increase in prescribing drugs containing the same ingredient was observed for regimens containing various medicines. CONCLUSION More than 60% of the combinations were used together with other anti-glaucoma drugs. The advantages of these fixed dose combinations in improving patient compliance need to be reassessed in real-word settings. Prescriptions containing duplicated ingredients were common. However, they were not necessarily considered unreasonable because the dosage forms were administered at different times. For prescriptions containing repetitive ingredients, pharmacists should judge the rationale by evaluating the dosing frequency and drug indications and explain the appropriate administration to patients.