Ocular PhysiologyNCT00280462
Choroidal Blood Flow Regulation During Isometric Exercise: Effects of Ca2+-Channel Blockade
A study testing Nifedipine (drug) and L-Arginin (drug) in people with Ocular Physiology and Regional Blood Flow, run by Medical University of Vienna at 1 site in Austria.
Trial summary
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. Read more about this study
- Who is it for?
- Ages 19 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Ocular Physiology, Regional Blood Flow
- What is being tested?
- Nifedipine (drug) and L-Arginin (drug)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 21 participants
- Where
- 1 siteAustria
- Study dates
- Aug 2005to Apr 2006
- Phase
- Interventional
- 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 19 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropy more than 3 Dpt.
Who cannot join
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. In a previous project we were able to identify that the nitric oxide (NO) - system as well as the endothelin system are involved in choroidal blood flow regulation during isometric exercise.
In the present study autoregulation of the choroid during isometric exercise will be investigated and the pressure/flow relationships will be observed in the absence or presence of a calcium antagonist - nifedipine.
- Conditions
- Ocular Physiology, Regional Blood Flow
- Being tested
- Nifedipine (drug), L-Arginin (drug), Placebo
- Keywords
- Nifedipine, Choroidal blood flow, Choroidal autoregulation, Isometric exercise
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nifedipine (drug)Drug
Nifedipine (Adalat®, Bayer, Leverkusen, Germany) dose: 15µg/kg bolus infusion over 5 minutes; 0.2 µg/(kg.min) maintenance dose infusion period 25 minutes
L-Arginin (drug)Drug
L-Arginin (Clinalfa AG, Läufelfingen, Switzerland) 30% sodium chlorid solution, dose: 1g/min over 30 minutes
PlaceboDrug
Placebo
| Study group | Role | What they receive |
|---|---|---|
| 1 | Active comparator | Nifedipine Receives: Drug: Nifedipine (drug); Drug: L-Arginin (drug); Drug: Placebo |
| 2 | Active comparator | L-Arginin Receives: Drug: Nifedipine (drug); Drug: L-Arginin (drug); Drug: Placebo |
| 3 | Placebo comparator | Placebo Receives: Drug: Nifedipine (drug); Drug: L-Arginin (drug); Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Choroidal pressure-blood flow relationship
Measured: in total 3x 3 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Jan 2006 (estimated)
- Study startAug 2005
- Primary completionApr 2006
- Study completionApr 2006
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Ocular PhysiologyStudies 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 N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 21 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Investigators
- Gabriele Fuchsjäger-Mayrl, M.D., Principal investigator, Department of Clinical Pharmacology, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00280462
- Sponsor's protocol ID
- OPHT-110705
- Status last verified
- Jul 2008
- First submitted
- 19 Jan 2006
- Last updated
- 9 Jul 2008
- Results posted
- No
- Data monitoring committee
- Yes
Publications
Schmidl D, Prinz A, Kolodjaschna J, Polska E, Luksch A, Fuchsjager-Mayrl G, Garhofer G, Schmetterer L. Effect of nifedipine on choroidal blood flow regulation during isometric exercise. Invest Ophthalmol Vis Sci. 2012 Jan 25;53(1):374-8. doi: 10.1167/iovs.11-8536.
PubMed 22199246
Study at a glance
From the registry record, last updated by the sponsor on 9 Jul 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Choroidal Blood Flow Regulation During Isometric Exercise: Effects of Ca2+-Channel Blockade
- ClinicalTrials.gov ID
- NCT00280462
- Acronym / sponsor ID
- OPHT-110705
- Conditions
- Ocular Physiology, Regional Blood Flow
- Keywords
- Nifedipine, Choroidal blood flow, Choroidal autoregulation, Isometric exercise
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 21 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- Aug 2005
- Primary completion
- Apr 2006 (actual)
- Study completion
- Apr 2006 (actual)
- First posted
- 23 Jan 2006 (estimated)
- 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.
Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. In a previous project we were able to identify that the nitric oxide (NO) - system as well as the endothelin system are involved in choroidal blood flow regulation during isometric exercise.
In the present study autoregulation of the choroid during isometric exercise will be investigated and the pressure/flow relationships will be observed in the absence or presence of a calcium antagonist - nifedipine.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 1 | Active comparator | Drug: Nifedipine (drug), Drug: L-Arginin (drug), Drug: PlaceboNifedipine |
| 2 | Active comparator | Drug: Nifedipine (drug), Drug: L-Arginin (drug), Drug: PlaceboL-Arginin |
| 3 | Placebo comparator | Drug: Nifedipine (drug), Drug: L-Arginin (drug), Drug: PlaceboPlacebo |
Who may qualify
- Ages
- 19 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Men aged between 19 and 35 years, nonsmokers
- Body mass index between 15th and 85th percentile (Must et al. 1991)
- Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
- Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
- Normal ophthalmic findings, ametropy more than 3 Dpt.
Key exclusion criteria (6 listed)
- Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
- History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
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 |
|---|---|---|
| Nifedipine (drug)Nifedipine (Adalat®, Bayer, Leverkusen, Germany) dose: 15µg/kg bolus infusion over 5 minutes; 0.2 µg/(kg.min) maintenance dose infusion period 25 minutes | Drug | 1, 2, 3 |
| L-Arginin (drug)L-Arginin (Clinalfa AG, Läufelfingen, Switzerland) 30% sodium chlorid solution, dose: 1g/min over 30 minutes | Drug | 1, 2, 3 |
| PlaceboPlacebo | Drug | 1, 2, 3 |
Primary outcome
Choroidal pressure-blood flow relationship
Time frame: in total 3x 3 hours
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 9 Jul 2008.
- Derived from this study: PubMed 22199246Schmidl D, Prinz A, Kolodjaschna J, Polska E, Luksch A, Fuchsjager-Mayrl G, Garhofer G, Schmetterer L. Effect of nifedipine on choroidal blood flow regulation during isometric exercise. Invest Ophthalmol Vis Sci. 2012 Jan 25;53(1):374-8. doi: 10.1167/iovs.11-8536.
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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.
Gabriele Fuchsjäger-Mayrl, M.D. principal investigator
Department of Clinical Pharmacology, Medical University of Vienna
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nifedipine (drug) and L-Arginin (drug) in people with Ocular Physiology and Regional 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 5 inclusion and 6 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 9 Jul 2008. 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.
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?
Choroidal pressure-blood flow relationship (time frame: in total 3x 3 hours). 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 NCT00280462, which also lists 1 linked publication.
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 9 Jul 2008.