The Effect of Dronabinol on Ocular Hemodynamics in Patients With Primary Open Angle Glaucoma

Inclusion Criteria: * Diagnosis of manifest open angle glaucoma as defined as pathological optic disc appearance, glaucoma hemifield test outside normal limits and/or untreated IOP ≥ 21 mmHg on at least three measurements in the medical history. * Mean deviation in the visual field test \< 10dB * Informed consent signed and dated * Patient aged ≥ 18 years old * Ametropia ≤ 6 diopters * Normal findings in the medical history and physical examination including ECG unless the investigator considers an abnormality to be clinically irrelevant * Normal findings in the laboratory testing unless the investigator considers an abnormality to be clinically irrelevant * Nonsmokers Exclusion Criteria: * Exfoliation glaucoma * Pigmentary glaucoma * Secondary glaucoma * History of acute angle closure * Intraocular surgery within the last 6 months * Filtration surgery for glaucoma at any time * Laser procedure for glaucoma within the last 12 months Visual field not performed or not available within 6 months * Ocular inflammation or infection within the last 3 months * Regular use of medication that potentially could interact with THC, abuse of alcoholic beverages or drugs * History of drug or alcohol abuse * Psychiatric disorders in the medical history * Risk for drug dependence as evaluated by a psychiatrist * Participation in a clinical trial in the 3 weeks preceding the study * Positive urine drug test at the screening examination or on the study days * Positive alcohol breath test at the screening examination or on the study days * Regular consumption of cannabis and inability to not consume cannabis during the study period * Symptoms of a clinically relevant illness in the 3 weeks before the first study day * History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with distribution, metabolism or excretion of study drugs * Blood donation during the previous 3 weeks * Known hypersensitivity to any of the components of the IMP under investigation or other study medication * History or family history of epilepsy * Pregnant or breast-feeding women * Women of childbearing potential (neither menopausal, nor hysterectomized, nor sterilized) not using effective contraception (oral contraceptives, intra-uterine device, contraceptive implant or condoms)