title: Effect of sublingual application of cannabinoids on intraocular pressure: a pilot study.
abstract: OBJECTIVE
  The purpose of this study was to assess the effect on intraocular pressure (IOP) and the safety and tolerability of oromucosal administration of a low dose of delta-9-tetrahydrocannabinol (Delta-9-THC) and cannabidiol (CBD).
  
  
  METHODS
  A randomized, double-masked, placebo-controlled, 4 way crossover study was conducted at a single center, using cannabis-based medicinal extract of Delta-9-THC and CBD. Six patients with ocular hypertension or early primary open angle glaucoma received a single sublingual dose at 8 AM of 5 mg Delta-9-THC, 20 mg CBD, 40 mg CBD, or placebo. Main outcome measure was IOP. Secondary outcomes included visual acuity, vital signs, and psychotropic effects.
  
  
  RESULTS
  Two hours after sublingual administration of 5 mg Delta-9-THC, the IOP was significantly lower than after placebo (23.5 mm Hg vs. 27.3 mm Hg, P=0.026). The IOP returned to baseline level after the 4-hour IOP measurement. CBD administration did not reduce the IOP at any time. However, the higher dose of CBD (40 mg) produced a transient elevation of IOP at 4 hours after administration, from 23.2 to 25.9 mm Hg (P=0.028). Vital signs and visual acuity were not significantly changed. One patient experienced a transient and mild paniclike reaction after Delta-9-THC administration.
  
  
  CONCLUSIONS
  A single 5 mg sublingual dose of Delta-9-THC reduced the IOP temporarily and was well tolerated by most patients. Sublingual administration of 20 mg CBD did not reduce IOP, whereas 40 mg CBD produced a transient increase IOP rise.
authors.affiliation: Department of Ophthalmology, Aberdeen Royal Infirmary, Institute of Medical Sciences, University of Aberdeen, UK.
authors.forename: Ileana
authors.initials: I
authors.lastname: Tomida
authors.forename: Augusto
authors.initials: A
authors.lastname: Azuara-Blanco
authors.forename: Heather
authors.initials: H
authors.lastname: House
authors.forename: Maggie
authors.initials: M
authors.lastname: Flint
authors.forename: Roger G
authors.initials: RG
authors.lastname: Pertwee
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Robson
mesh_terms: D000286:Administration, Sublingual; D002185:Cannabidiol / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D013759:Dronabinol / Q000008:administration & dosage*; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy; D010865:Pilot Projects; D011619:Psychotropic Drugs / Q000008:administration & dosage*; D014792:Visual Acuity / Q000187:drug effects
chemical_list: D011619:Psychotropic Drugs; D002185:Cannabidiol; D013759:Dronabinol