The effects of forskolin eye drops on intra-ocular pressure

Two studies were performed to investigate the effects of forskolin (Hoechst Research) on intra-ocular pressure (IOP). In the first study two 1.0% formulations of forskolin eye drops were compared with placebo in 10 healthy volunteers. Oxybuprocaine eye drops were used for local anaesthesia before measurement of IOP by applanation tonometry. This was followed by instillation of either medication or placebo on a randomised cross-over basis and hourly measurement of IOP. No significant differences were present between the forskolin treatments and placebo. For 6 hours after drug application a definite decrease in IOP relative to base-line values was observed after each of the forskolin treatments as well as after placebo. In a subsequent study only one formulation of 1% forskolin was compared with placebo. Proxymetacaine eye drops were used for local anaesthesia. Forskolin resulted in a significant reduction in IOP relative to placebo. It is concluded that forskolin reduces IOP in healthy volunteers, and that oxybuprocaine reduces IOP in its own right.