Trial Review

Did you know?

The ANZCTR now automatically displays published trial results and simplifies the addition of trial documents such as unpublished protocols and statistical analysis plans.

These enhancements will offer a more comprehensive view of trials, regardless of whether their results are positive, negative, or inconclusive.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
ACTRN12624001010583
Ethics application status
Approved
Date submitted
22/05/2024
Date registered
20/08/2024
Date last updated
20/08/2024
Date data sharing statement initially provided
20/08/2024
Type of registration
Retrospectively registered

Titles & IDs
Public title
Does levodopa/carbidopa, a common Parkinson's Disease drug, affect stomach emptying, blood pressure and heart rate?
Scientific title
Acute effects of dopaminergic therapy with levodopa/carbidopa on the gastric emptying, blood pressure and superior mesenteric artery blood flow responses to oral glucose in patients with mild to moderate Parkinson’s disease.
Secondary ID [1] 293613 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Parkinson's disease 305875 0
Postprandial hypotension 333989 0
Delayed gastric emptying 333990 0
Condition category
Condition code
Oral and Gastrointestinal 305076 305076 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon
Cardiovascular 305077 305077 0 0
Diseases of the vasculature and circulation including the lymphatic system
Metabolic and Endocrine 305078 305078 0 0
Other metabolic disorders
Neurological 330656 330656 0 0
Parkinson's disease
Cardiovascular 330657 330657 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Patients will attend on two separate occasions (after fasting from solids for 14 h and liquids for 12 h) at least five days apart.

At t= -60 minutes, the patient will then be given either
(1) an oral dose of levodopa (200mg)/carbidopa (50mg) (tablet) or
(2) matching placebo.

At t = -3 min, the patient will consume a drink comprising 75 g glucose labelled with 20 MBq 99mTc-calcium phytate, made up to 300ml water. The end of drink consumption will be recorded as t = 0 min

Patients will then undergo concurrent measurements of gastrointestinal (GI) symptoms (questionnaire), gastric emptying (scintigraphy) , blood pressure, heart rate (Dinamap) and superior mesenteric artery blood flow (Doppler ultrasound), blood glucose , serum insulin , and plasma levodopa (L-DOPA) concentrations for a period of 3 hours i.e. t= 0-180 min, following the drink.
Intervention code [1] 299876 0
Treatment: Drugs
Comparator / control treatment
The effect of levodopa/carbidopa on the gastric emptying, blood pressure and superior mesenteric artery blood flow responses to oral glucose in patients will be compared to matched placebo (control- containing sucralose)
Control group
Placebo

Outcomes
Primary outcome [1] 304258 0
Gastric emptying using Scintigraphy
Timepoint [1] 304258 0
Gastric emptying will be measured continuously during the study (t=0-180 min) ie 1 min frames for the first 60 min and 3 min frames thereafter until t=180 min.
Secondary outcome [1] 341379 0
Blood pressure using automated BP cuff (DINAMAP ProCare 100, GE Medical Systems, Milwaukee, WI, USA).
Timepoint [1] 341379 0
Blood pressure will be measured at 3 min intervals for 9 min prior to administration of study drug, continuously prior to the ingestion of the drink (t = -60, -45, -30, -15, -3 minutes), and then regularly at 3-min intervals from t = 0 - 180 min.
Secondary outcome [2] 341380 0
Heart rate using automated BP cuff (DINAMAP ProCare 100, GE Medical Systems, Milwaukee, WI, USA).
Timepoint [2] 341380 0
Blood pressure will be measured at 3 min intervals for 9 min prior to administration of study drug, continuously prior to the ingestion of the drink (t = -60, -45, -30, -15, -3 minutes), and then regularly at 3-min intervals from t = 0 - 180 min.
Secondary outcome [3] 341381 0
SMA blood flow using a Logiq GE doppler ultrasonography system (GE Healthcare Technologies, Sydney, NSW, Australia).
Timepoint [3] 341381 0
SMA blood flow will be measured immediately before the study medication (t = -60 minutes) and before the drink consumption (t= -30 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120, 150 and 180 minutes.
Secondary outcome [4] 341382 0
Sensation of dizziness using a visual analogue scale.
Timepoint [4] 341382 0
Prior to the ingestion of the drink (t = -60, -30 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120 and 180 minutes.
Secondary outcome [5] 341383 0
Blood glucose using a portable blood glucose meter (MediSense Companion 2 meter; MediSense Inc., Waltham, MA)
Timepoint [5] 341383 0
Blood glucose will be measured prior to the ingestion of the drink (t = -60, -45, -30, -15 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120, 150, 180.
Secondary outcome [6] 341384 0
Insulin using serum samples
Timepoint [6] 341384 0
Serum insulin will be measured prior to the ingestion of the drink (t = -60, -45, -30, -15 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120, 150, 180.
Secondary outcome [7] 341385 0
Levodopa level using plasma samples
Timepoint [7] 341385 0
Levodopa level will be measured prior to the ingestion of the drink (t = -60, -45, -30, -15 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120, 150, 180.
Secondary outcome [8] 437993 0
Sensation of hunger with visual analogue questionnaire
Timepoint [8] 437993 0
Prior to the ingestion of the drink (t = -60, -30 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120 and 180 minutes.
Secondary outcome [9] 437994 0
Sensation of fullness with visual analogue questionnaire
Timepoint [9] 437994 0
Prior to the ingestion of the drink (t = -60, -30 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120 and 180 minutes.
Secondary outcome [10] 437995 0
Sensation of desire to eat with visual analogue questionnaire
Timepoint [10] 437995 0
Prior to the ingestion of the drink (t = -60, -30 and -3 minutes) and then at t = 15, 30, 45, 60, 90, 120 and 180 minutes.

Eligibility
Key inclusion criteria
• Patients currently taking short-acting levodopa/carbidopa
• Body Mass Index (BMI) 19 - 30 kg/m²
• A diagnosis of idiopathic PD according to the UK brain bank criteria of mild to moderate PD (Hoehn and Yahr Staging <2.5)
Minimum age
50 Years
Maximum age
80 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
• History of diabetes mellitus (or fasting plasma glucose >7.0 mmol/L or HbA1C > or =6.5%), severe respiratory, cardiovascular, haematologic, hepatic and/or renal disease (creatinine clearance <50 mL/min), chronic alcohol abuse or epilepsy or if iron stores, or liver function tests are two times greater than the upper limit of the following normal ranges:

Alanine aminotransferase (ALT) < 55 U/L
Alkaline phosphatase (ALP) 30 - 110 U/L
Aspartate transaminase (AST) < 45 U/L
Total bilirubin 2 - 24 µmol/L
Haemoglobin 115 – 165 g/L (Females)
130 – 180 g/L (Males)
Ferritin 15 – 200 µg/L (Females)
30 – 300 µg/L (Males)

• Medication that influence BP or GI function
• Patients taking long-acting levodopa preparations
• History of GI disease (unrelated to PD), including known gastroparesis, significant upper GI symptoms and gastric surgery
• Smoking >10 cigarettes/day
• Alcohol consumption > 20 g/day
• Blood donation in the previous 12 weeks
• Pregnancy or breastfeeding
• Inability to withdraw from the morning dose of anti-Parkinsonian medication to allow a washout.
• Contraindications to levodopa/carbidopa, including current treatment with MAO inhibitor, known hypersensitivity, narrow-angle glaucoma, melanoma and suspicious undiagnosed skin lesions.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomisation will be carried out by the Pharmacy at the Royal Adelaide Hospital. Allocation will involve contacting the holder of the allocation schedule (RAH Pharmacy) who is at a separate site to provide the medication (so that this is blinded to both the participant and study investigator).
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Sequence generation will be carried out by the Pharmacy at the Royal Adelaide Hospital using simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation).
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Data will be analysed using standardised, non-parametric statistical methods (e.g. using repeated measures ANOVA). Relationships between variables will be assessed by linear regression analysis.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
20/09/2018
Date of last participant enrolment
Anticipated
30/11/2025
Actual
Date of last data collection
Anticipated
31/12/2025
Actual
Sample size
Target
20
Accrual to date
9
Final
Recruitment in Australia
Recruitment state(s)
SA
Recruitment hospital [1] 9570 0
The Royal Adelaide Hospital - Adelaide
Recruitment postcode(s) [1] 18323 0
5000 - Adelaide

Funding & Sponsors
Funding source category [1] 298226 0
Hospital
Name [1] 298226 0
Royal Adelaide Hospital Clinical Project Grant
Country [1] 298226 0
Australia
Primary sponsor type
Individual
Name
Professor Karen Jones, The University of Adelaide
Address
NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Level 5 Adelaide Health and Medical Sciences Building, Cnr North Tce and George St, Adelaide, SA 5005
Country
Australia
Secondary sponsor category [1] 297342 0
None
Name [1] 297342 0
Address [1] 297342 0
Country [1] 297342 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 299235 0
Central Adelaide Local Health Network HREC
Ethics committee address [1] 299235 0
https://www.rah.sa.gov.au/research/for-researchers/central-adelaide-local-health-network-human-research-ethics-committee
Ethics committee country [1] 299235 0
Australia
Date submitted for ethics approval [1] 299235 0
30/11/2016
Approval date [1] 299235 0
13/06/2017
Ethics approval number [1] 299235 0
R20161203

Summary
Brief summary
In this study, we are interested in looking at the acute effects of the anti-Parkinson drug, levodopa/carbidopa (Sinemet®) on the rate of stomach emptying, blood pressure and abdominal blood flow after a sugary drink, and the relationship between the rate of stomach emptying and the rise in levodopa levels.

The primary hypotheses underlying the study are that (i) a therapeutic dose of levodopa (200mg) / carbidopa (50mg) will slow gastric emptying in patients with mild to moderate Parkinson’s disease and (ii) this slowing of gastric emptying will be associated with an attenuation in the fall in blood pressure, and the rise in superior mesenteric artery (SMA) blood flow, after oral glucose.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 79750 0
Prof Karen Jones
Address 79750 0
NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Level 5 Adelaide Health and Medical Sciences Building, Cnr North Tce and George St, Adelaide, SA 5005, Australia
Country 79750 0
Australia
Phone 79750 0
+61 8 8313 7821
Fax 79750 0
Email 79750 0
[email protected]
Contact person for public queries
Name 79751 0
Karen Jones
Address 79751 0
The University of Adelaide, Level 5 Adelaide Health and Medical Sciences Building Cnr North Tce and George St Adelaide SA 5005 Australia
Country 79751 0
Australia
Phone 79751 0
+61 8 8313 7821
Fax 79751 0
Email 79751 0
[email protected]
Contact person for scientific queries
Name 79752 0
Karen Jones
Address 79752 0
The University of Adelaide, Level 5 Adelaide Health and Medical Sciences Building Cnr North Tce and George St Adelaide SA 5005 Australia
Country 79752 0
Australia
Phone 79752 0
+61 8 8313 7821
Fax 79752 0
Email 79752 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Data are to remain confidential to maintain participant anonymity


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.