The Effect of Tetrahydrocannabinol on Ocular Hemodynamics in Healthy Subjects
Status:
Completed
Trial end date:
2018-11-27
Target enrollment:
Participant gender:
Summary
Glaucoma is among the leading causes for irreversible blindness worldwide. While lowering
intraocular pressure (IOP) remains the mainstay of therapy, there are still some patients who
progress despite wellcontrolled IOP. There is evidence from several studies that ocular blood
flow and its regulation is impaired in patients with glaucoma. Tetrahydrocannabinol (THC) has
been used in the treatment for glaucoma in some countries for several years due to its IOP
lowering effect. In addition, there is also evidence that THC features neuroprotective
effects and improves ocular hemodynamics. Dronabinol is a synthetic THC that is legally
available in several European countries. It has the advantage that exact dosing of THC is
possible in contrast to previously applied administration forms such as smoking. Due to its
legal status in the past, data about the effect of THC on ocular blood flow and its
regulation are sparse. This holds true for basic research in healthy subjects as well as in
patients with glaucoma.The aim of the present study therefore is to investigate whether
single administration of THC alters optic nerve head (ONH) blood flow in healthy subjects. In
addition, other parameters for ocular blood flow will be measured, in particular retinal
blood flow, retinal oxygen saturation and retinal neurovascular coupling. The study will be
conducted in a randomized, double-masked, placebocontrolled, two-way cross-over design.
Subjects will receive 5mg dronabinol on one study day. This dose is the recommended starting
dose for some indications in clinical practice. Other studies investigating retinal
hemodynamics or IOP after administration of THC also have used similar or slightly higher
doses.