Retinal Blood FlowPhase 2NCT04596826
The Effect of Dronabinol on Ocular Hemodynamics in Patients With Primary Open Angle Glaucoma
A Phase 2 study testing Dronabinol 5 MG and Dronabinol 10 MG in people with Retinal Blood Flow, run by Medical University of Vienna at 1 site in Austria.
Trial 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 well-controlled IOP. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Retinal Blood Flow
- What is being tested?
- Dronabinol 5 MG and Dronabinol 10 MG
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 51 participants
- Where
- 1 siteAustria
- Study dates
- 11 Nov 2020to 2 Oct 2024
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Show all 23Show fewer
- 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)
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University Vienna
Vienna, 1090
About this study
Official title: The Effect of Dronabinol on Ocular Hemodynamics in Patients With Primary
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 well-controlled 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. In a recent study conducted in the investigators laboratory they found that single administration of dronabinol leads to a significant increase in optic nerve head (ONH) blood flow without impairing its autoregulatory capacity.The aim of the present study therefore is to investigate whether single administration of dronabinol alters optic nerve head (ONH) blood flow in patients with open angle glaucoma. 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 parallel-group, randomized, double-masked, placebo-controlled, cross-over design. Patients will be randomized to either receive 5mg or 10mg dronabinol on one study day. Other studies investigating retinal hemodynamics or IOP after administration of THC also have used similar or slightly higher doses.
- Conditions
- Retinal Blood Flow
- Being tested
- Dronabinol 5 MG, Dronabinol 10 MG, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dronabinol 5 MGDrug
oral administration
Dronabinol 10 MGDrug
oral administration
PlaceboDrug
oral administration
| Study group | Role | What they receive |
|---|---|---|
| healthy subjects | Experimental | Not described Receives: Drug: Dronabinol 5 MG; Drug: Dronabinol 10 MG; Drug: Placebo |
| glaucoma patients | Experimental | Not described Receives: Drug: Dronabinol 5 MG; Drug: Dronabinol 10 MG; Drug: Placebo |
| healthy volunteers | Placebo comparator | Not described Receives: Drug: Dronabinol 5 MG; Drug: Dronabinol 10 MG; Drug: Placebo |
| Glaucoma patients | Placebo comparator | Not described Receives: Drug: Dronabinol 5 MG; Drug: Dronabinol 10 MG; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Optic nerve head blood flow
To determine the total blood flow in the eye, OCT measurements were performed with a rectangular scanning pattern around the optical nerve head.
Measured: 60 minutes on the study day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Oct 2020
- Study start11 Nov 2020
- Primary completion2 Oct 2024
- Study completion2 Oct 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Retinal Blood FlowStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 51 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Doreen Schmidl, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04596826
- Sponsor's protocol ID
- OPHT-250719
- Status last verified
- Dec 2023
- First submitted
- 14 Oct 2020
- Last updated
- 16 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Lindner T, Pai V, Janku P, Hommer N, Hommer A, Petric L, Graf U, Schmetterer L, Garhofer G, Schmidl D. Optic nerve head blood flow autoregulation during isometric exercise in primary open-angle glaucoma assessed by laser speckle flowgraphy. Acta Ophthalmol. 2026 Aug 22. doi: 10.1111/aos.70230. Online ahead of print.
PubMed 42631643Lindner T, Pai V, Janku P, Hommer N, Hommer A, Abensperg-Traun M, Petric L, Schmetterer L, Garhofer G, Schmidl D. Single oral administration of dronabinol increases ocular blood flow in patients with glaucoma. Acta Ophthalmol. 2026 Mar;104(2):225-232. doi: 10.1111/aos.17573. Epub 2025 Aug 7.
PubMed 40772417
Study at a glance
From the registry record, last updated by the sponsor on 16 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Dronabinol on Ocular Hemodynamics in Patients With Primary
- ClinicalTrials.gov ID
- NCT04596826
- Acronym / sponsor ID
- OPHT-250719
- Conditions
- Retinal Blood Flow
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 51 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- 11 Nov 2020 (actual)
- Primary completion
- 2 Oct 2024 (actual)
- Study completion
- 2 Oct 2024 (actual)
- First posted
- 22 Oct 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 well-controlled 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. In a recent study conducted in the investigators laboratory they found that single administration of dronabinol leads to a significant increase in optic nerve head (ONH) blood flow without impairing its autoregulatory capacity.The aim of the present study therefore is to investigate whether single administration of dronabinol alters optic nerve head (ONH) blood flow in patients with open angle glaucoma. 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 parallel-group, randomized, double-masked, placebo-controlled, cross-over design. Patients will be randomized to either receive 5mg or 10mg dronabinol on one study day. Other studies investigating retinal hemodynamics or IOP after administration of THC also have used similar or slightly higher doses.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| healthy subjects | Experimental | Drug: Dronabinol 5 MG, Drug: Dronabinol 10 MG, Drug: Placebo |
| glaucoma patients | Experimental | Drug: Dronabinol 5 MG, Drug: Dronabinol 10 MG, Drug: Placebo |
| healthy volunteers | Placebo comparator | Drug: Dronabinol 5 MG, Drug: Dronabinol 10 MG, Drug: Placebo |
| Glaucoma patients | Placebo comparator | Drug: Dronabinol 5 MG, Drug: Dronabinol 10 MG, Drug: Placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- 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.
Key exclusion criteria (23 listed)
- Exfoliation glaucoma
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dronabinol 5 MGoral administration | Drug | Glaucoma patients, glaucoma patients, healthy subjects, healthy volunteers |
| Dronabinol 10 MGoral administration | Drug | Glaucoma patients, glaucoma patients, healthy subjects, healthy volunteers |
| Placebooral administration | Drug | Glaucoma patients, glaucoma patients, healthy subjects, healthy volunteers |
Primary outcome
Optic nerve head blood flow
Time frame: 60 minutes on the study day
To determine the total blood flow in the eye, OCT measurements were performed with a rectangular scanning pattern around the optical nerve head.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 May 2025.
- Derived from this study: PubMed 42631643Lindner T, Pai V, Janku P, Hommer N, Hommer A, Petric L, Graf U, Schmetterer L, Garhofer G, Schmidl D. Optic nerve head blood flow autoregulation during isometric exercise in primary open-angle glaucoma assessed by laser speckle flowgraphy. Acta Ophthalmol. 2026 Aug 22. doi: 10.1111/aos.70230. Online ahead of print.
- Derived from this study: PubMed 40772417Lindner T, Pai V, Janku P, Hommer N, Hommer A, Abensperg-Traun M, Petric L, Schmetterer L, Garhofer G, Schmidl D. Single oral administration of dronabinol increases ocular blood flow in patients with glaucoma. Acta Ophthalmol. 2026 Mar;104(2):225-232. doi: 10.1111/aos.17573. Epub 2025 Aug 7.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Dronabinol 5 MG and Dronabinol 10 MG in people with Retinal Blood Flow, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 23 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Optic nerve head blood flow (time frame: 60 minutes on the study day). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04596826, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 May 2025.