Daily cost of newer glaucoma agents

The purpose of this study was to evaluate the drop characteristics of newer glaucoma medicines compared to timolol solution and timolol gel forming solution (Timoptic-XE, Merck). We evaluated latanoprost 0.005% (2.5 ml bottle), brimonidine 0.2%, apraclonidine 0.5%, dorzolamide 2%, timolol solution 0.5% (5 and 10 ml bottles), and timolol gel forming solution 0.5% (5 ml bottle) in 14 patients with primary open-angle glaucoma or ocular hypertension. Each patient placed 10 drops onto an analytical scale (one drop every 10 seconds) for all ten preparations. Patients then attempted to instill 10 drops of a tear replacement solution into their ocular cul-de-sac. Medication bottles were weighed before and after patients dispensed from the bottle and then after the bottle was emptied. Weights were converted to volume using the density of the medicine. A statistical difference existed between groups for mean drop volume with latanoprost having the smallest drop volume (.0273 +/- .004 ml) (P<0.005). All manufacturers filled correctly or overfilled their bottles with product and had <10% of medicine wasted. Patients instilled 77.9% of the tear solution correctly. When dosed according to labeling, latanoprost had the lowest cost of therapy at $0.87 daily compared to the other newly released medications (range $1.05 to $1.40). Latanoprost was more expensive, however, than timolol maleate solution or gel (range $0.45 to $0.54 per day). Latanoprost therapy is less expensive per day than dorzolamide, brimonidine or apraclonidine, but more expensive than timolol maleate. Cost per day could be further reduced by limiting medicine wastage upon instillation, however.