The duration of effectiveness of single instillations of 4% and 8% pilocarpine in one eye of a number of patients with ocular hypertension was observed. Both 4% and 8% pilocarpine were still effective in lowering intraocular pressure at the end of 12 hours, after which time the pressures started to rise. A statistically significant drug effect still persisted 15 hours after administration.
Drance SM, Bensted M, Schulzer M. Pilocarpine and Intraocular PressureDuration of Effectiveness of 4% and 8% Pilocarpine Instillation. Arch Ophthalmol. 1974;91(2):104-106. doi:10.1001/archopht.1974.03900060110004