Placebo EffectNCT01501747
The Placebo Effect May Involve Modulating Drug Bioavailability
A study testing Caffeine, paracetamol, cephalexin, or ibuprofen in people with Placebo Effect and Drug Half Life, run by King Faisal Specialist Hospital & Research Center at 1 site in Saudi Arabia.
Trial summary
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their interaction. Current interpretation of clinical trials (the gold standard of evidence-based-medicine) assumes no interaction, and the mechanism(s) underlying such interaction have not been fully… Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Placebo Effect, Drug Half Life, Pharmacokinetics
- What is being tested?
- Caffeine, paracetamol, cephalexin, or ibuprofen
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 162 participants
- Where
- 1 siteSaudi Arabia
- Study dates
- Feb 2012to Feb 2013
- 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 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Having no evidence of clinically important deviation from normal health as indicated by medical history, vital signs, and clinical laboratory tests.
- Acceptance to abstain from taking any medication other than birth control pills (including over-the-counter drugs) for at least 1 week prior to, and during the study; and from smoking and taking alcohol or caffeine or related xanthenes-containing beverages or food for 48 hours before and throughout each study period.
- Having good peripheral venous access.
- For the caffeine study, habitual daily caffeine intake should be 100-300 mg.
Who cannot join
- Women should be non-pregnant and non-lactating. For menstruating women, the study will be conducted 5 to 19 days after the last menstrual period and a urine pregnancy test will be performed.
- Should not have history of hypersensitivity to the drug to be tested or to its related compounds.
- Body Mass Index (BMI) should be less than 35 kg/m2.
Trial locations and contacts
1 site in 1 country.
Saudi Arabia1 site
King Faisal Specialist Hospital & Research Center
Riyadh, 11211
About this study
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their interaction. Current interpretation of clinical trials (the gold standard of evidence-based-medicine) assumes no interaction, and the mechanism(s) underlying such interaction have not been fully explored. One possibility is that the placebo effect may modulate drug bioavailability. Using caffeine as a model drug, we have recently shown that the placebo effect of caffeine ingestion prolongs caffeine half life. Due to the novelty of this finding and its important clinical practice and clinical research implications, it needs to be confirmed in another set of subjects and extended to additional drugs.
The results of the study are expected to further our understanding of the mechanism of action of a widely used medical intervention, i.e., placebo. The results will be important for both clinical practice and clinical research.
Read the detailed description
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their interaction. Current interpretation of clinical trials (the gold standard of evidence-based-medicine) assumes no interaction, and the mechanism(s) underlying such interaction have not been fully explored. One possibility is that the placebo effect may modulate drug bioavailability. Using caffeine as a model drug, we have recently shown that the placebo effect of caffeine ingestion prolongs caffeine half life. Due to the novelty of this finding and its important clinical practice and clinical research implications, it needs to be confirmed in another set of subjects and extended to additional drugs.
DESIGN: Balanced cross-over, single-dose, two-period, two-group deign comparing caffeine, paracetamol, cephalexin, and ibuprofen described as such (overt) to the same medication described as placebo (covert).
METHODS: 32, 50, 50, and 30 healthy adult volunteers will be enrolled in the caffeine (300 mg), paracetamol (500 mg), cephalexin (500 mg), and ibuprofen (400 mg) cross-over studies, respectively. Volunteers will be partially deceived to the intervention assignment (i.e., in the covert arm). Serum levels of each drug will be blindly determined by locally validated HPLC assays. Plasma half life (primary outcome) as well as Cmax, Tmax, and AUC (secondary outcomes) of each drug will be determined and analyzed by ANOVA.
- Conditions
- Placebo Effect, Drug Half Life, Pharmacokinetics
- Being tested
- Caffeine, paracetamol, cephalexin, or ibuprofen, Placebo (caffeine, paracetamol, cephalexin, or ibuprofen)
- Keywords
- Placebo effect, drug half life, pharmacokinetics
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Caffeine, paracetamol, cephalexin, or ibuprofenDrug
The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving the active drug.
Placebo (caffeine, paracetamol, cephalexin, or ibuprofen)Drug
The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving a placebo.
| Study group | Role | What they receive |
|---|---|---|
| overt drug | Active comparator | The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving such medication. Receives: Drug: Caffeine, paracetamol, cephalexin, or ibuprofen |
| Placebo (Covert drug) | Placebo comparator | The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving a placebo. Receives: Drug: Placebo (caffeine, paracetamol, cephalexin, or ibuprofen) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Plasma half life
The study has 4 sub-parts (one for eah of 4 drugs), each sub-part has a crossover design. The time frame to measure the outcome depends on the drug studied. For caffeine it is 24 hours, for paracetamol, it is 14 hours, for cephalexin, it is 6 hours, and for ibuprofen, it is 10 hours.
Measured: 24 hours
Secondary outcomes (3)
Area under the curve
The study has 4 sub-parts (one for eah of 4 drugs), each sub-part has a crossover design. The time frame to measure the outcome depends on the drug studied. For caffeine it is 24 hours, for paracetamol, it is 14 hours, for cephalexin, it is 6 hours, and for ibuprofen, it is 10 hours.
Measured: 24 hours
Tmax
The study has 4 sub-parts (one for eah of 4 drugs), each sub-part has a crossover design. The time frame to measure the outcome depends on the drug studied. For caffeine it is 24 hours, for paracetamol, it is 14 hours, for cephalexin, it is 6 hours, and for ibuprofen, it is 10 hours.
Measured: 24 hours
Cmax
The study has 4 sub-parts (one for eah of 4 drugs), each sub-part has a crossover design. The time frame to measure the outcome depends on the drug studied. For caffeine it is 24 hours, for paracetamol, it is 14 hours, for cephalexin, it is 6 hours, and for ibuprofen, it is 10 hours.
Measured: 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Dec 2011 (estimated)
- Study startFeb 2012
- Primary completionFeb 2013
- Study completionFeb 2013
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 Placebo EffectStudies of the same condition, open and under way.
- 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
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 162 participants (actual)
Sponsor and investigators
- Lead sponsor
- King Faisal Specialist Hospital & Research Center
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01501747
- Sponsor's protocol ID
- RAC2101105
- Status last verified
- Apr 2013
- First submitted
- 26 Dec 2011
- Last updated
- 9 Apr 2013
- Results posted
- No
- Data monitoring committee
- No
Publications
Hammami MM, Yusuf A, Shire FS, Hussein R, Al-Swayeh R. Does the placebo effect modulate drug bioavailability? Randomized cross-over studies of three drugs. J Negat Results Biomed. 2017 May 23;16(1):10. doi: 10.1186/s12952-017-0075-2.
PubMed 28535819
Study at a glance
From the registry record, last updated by the sponsor on 9 Apr 2013. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Placebo Effect May Involve Modulating Drug Bioavailability
- ClinicalTrials.gov ID
- NCT01501747
- Acronym / sponsor ID
- RAC2101105
- Conditions
- Placebo Effect, Drug Half Life, Pharmacokinetics
- Keywords
- Placebo effect, drug half life, pharmacokinetics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 162 participants (actual)
- Lead sponsor
- King Faisal Specialist Hospital & Research CenterUniversity, hospital or other
- Study start
- Feb 2012
- Primary completion
- Feb 2013 (actual)
- Study completion
- Feb 2013 (actual)
- First posted
- 29 Dec 2011 (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.
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their interaction. Current interpretation of clinical trials (the gold standard of evidence-based-medicine) assumes no interaction, and the mechanism(s) underlying such interaction have not been fully explored. One possibility is that the placebo effect may modulate drug bioavailability. Using caffeine as a model drug, we have recently shown that the placebo effect of caffeine ingestion prolongs caffeine half life. Due to the novelty of this finding and its important clinical practice and clinical research implications, it needs to be confirmed in another set of subjects and extended to additional drugs.
The results of the study are expected to further our understanding of the mechanism of action of a widely used medical intervention, i.e., placebo. The results will be important for both clinical practice and clinical research.
Detailed description
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their interaction. Current interpretation of clinical trials (the gold standard of evidence-based-medicine) assumes no interaction, and the mechanism(s) underlying such interaction have not been fully explored. One possibility is that the placebo effect may modulate drug bioavailability. Using caffeine as a model drug, we have recently shown that the placebo effect of caffeine ingestion prolongs caffeine half life. Due to the novelty of this finding and its important clinical practice and clinical research implications, it needs to be confirmed in another set of subjects and extended to additional drugs.
DESIGN: Balanced cross-over, single-dose, two-period, two-group deign comparing caffeine, paracetamol, cephalexin, and ibuprofen described as such (overt) to the same medication described as placebo (covert).
METHODS: 32, 50, 50, and 30 healthy adult volunteers will be enrolled in the caffeine (300 mg), paracetamol (500 mg), cephalexin (500 mg), and ibuprofen (400 mg) cross-over studies, respectively. Volunteers will be partially deceived to the intervention assignment (i.e., in the covert arm). Serum levels of each drug will be blindly determined by locally validated HPLC assays. Plasma half life (primary outcome) as well as Cmax, Tmax, and AUC (secondary outcomes) of each drug will be determined and analyzed by ANOVA.
Study design
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| overt drug | Active comparator | Drug: Caffeine, paracetamol, cephalexin, or ibuprofenThe study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving such medication. |
| Placebo (Covert drug) | Placebo comparator | Drug: Placebo (caffeine, paracetamol, cephalexin, or ibuprofen)The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving a placebo. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Having no evidence of clinically important deviation from normal health as indicated by medical history, vital signs, and clinical laboratory tests.
- Acceptance to abstain from taking any medication other than birth control pills (including over-the-counter drugs) for at least 1 week prior to, and during the study; and from smoking and taking alcohol or caffeine or related xanthenes-containing beverages or food for 48 hours before and throughout each study period.
- Having good peripheral venous access.
- For the caffeine study, habitual daily caffeine intake should be 100-300 mg.
Key exclusion criteria (3 listed)
- Women should be non-pregnant and non-lactating. For menstruating women, the study will be conducted 5 to 19 days after the last menstrual period and a urine pregnancy test will be performed.
- Should not have history of hypersensitivity to the drug to be tested or to its related compounds.
- Body Mass Index (BMI) should be less than 35 kg/m2.
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 |
|---|---|---|
| Caffeine, paracetamol, cephalexin, or ibuprofenThe study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving the active drug. | Drug | overt drug |
| Placebo (caffeine, paracetamol, cephalexin, or ibuprofen)The study has 4 sub-parts (one for each of 4 drugs), each sub-part has a crossover design. In this arm, the volunteer will be given one oral dose of 300 mg caffeine, 500 mg paracetamol, 500 mg cephalexin, or 400 mg ibuprofen and will be told that they are receiving a placebo. | Drug | Placebo (Covert drug) |
Primary outcome
Plasma half life
Time frame: 24 hours
The study has 4 sub-parts (one for eah of 4 drugs), each sub-part has a crossover design. The time frame to measure the outcome depends on the drug studied. For caffeine it is 24 hours, for paracetamol, it is 14 hours, for cephalexin, it is 6 hours, and for ibuprofen, it is 10 hours.
3 secondary outcomes
Area under the curve
Time frame: 24 hours
Tmax
Time frame: 24 hours
Cmax
Time frame: 24 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 Apr 2013.
- Derived from this study: PubMed 28535819Hammami MM, Yusuf A, Shire FS, Hussein R, Al-Swayeh R. Does the placebo effect modulate drug bioavailability? Randomized cross-over studies of three drugs. J Negat Results Biomed. 2017 May 23;16(1):10. doi: 10.1186/s12952-017-0075-2.
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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 study testing Caffeine, paracetamol, cephalexin, or ibuprofen in people with Placebo Effect and Drug Half Life, run by King Faisal Specialist Hospital & Research Center at 1 site in Saudi Arabia.
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 4 inclusion and 3 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 Apr 2013. 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 Saudi Arabia. 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?
Plasma half life (time frame: 24 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 NCT01501747, 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 Apr 2013; AzTrials last refreshed its copy on 3 Nov 2026.