Topical Δ⁹‐Tetrahydrocannabinol and Aqueous Dynamics in Glaucoma

Abstract

: Systemic Δ9‐tetrahydrocannabinol (THC), administered either by smoking marihuana or as synthetic THC in soft gelatin capsules, lowers ocular tension in various glaucomas, but at the expense of significant decreases in systolic blood pressure. Topical THC in light mineral oil vehicles, though effective in laboratory animals, was not shown effective in 0.05 and 0.1% topical solutions when administered to six subjects with primary open‐angle glaucoma in a randomized, balanced, double‐masked protocol. Light mineral oil, which has an affinity for corneal epithelium, is an optimum vehicle for administering drugs whose mechanisms of action are systemic rather than local within the eye. Further glaucoma research should therefore proceed with marihuanas containing insignificant levels of THC (less than 0.4%) and with various local delivery systems of the ocular‐active cannabinoid found in Cannabis sativa.

A Submicron Emulsion as Ocular Vehicle for Delta-8-Tetrahydro cannabinol: Effect on Intraocular Pressure in Rabbits

“…However, in clinical studies, the efficacy of topical administration was not clearly established [22] and sometimes was absent [17,23]. It should be emphasized that in these studies, A9-THC was dissolved in a mineral oil vehicle.…”

Cannabinoids in Health and Disease

“…[242][243][244] Marijuana smoking was shown to reduce IOP as early as 1971; the effect was later confirmed. [245][246][247][248] The peak effect of THC on the central nervous system coincided well with the reduction in intraocular pressure induced by the drug; However, hypotonia outlasted euphoria. The results indicate that THC may have value as a hypotonizing ocular drug.…”

A Synopsis of Recent Developments in Antiglaucoma Drugs

“…Treatment twice daily for 60 days gave a maximum hypotensive effect for 0.1% A -THC without tachyphylaxis in rabbits (159). Topical A9-THC (0.1% and 1%) in normal dogs gave equipotent ocular pressure decreases, attributed to reduction in AH formation (160). However, another study did not show significant IOP reduction in rabbits given doses of up to 1% A -THC using several different vehicles (11).…”