The Placebo Effect May Involve Modulating Drug Bioavailability
Information source: King Faisal Specialist Hospital & Research Center
ClinicalTrials.gov processed this data on August 23, 2015 Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Placebo Effect; Drug Half Life; Pharmacokinetics
Intervention: Caffeine, paracetamol, cephalexin, or ibuprofen (Drug); Placebo (caffeine, paracetamol, cephalexin, or ibuprofen) (Drug)
Phase: N/A
Status: Completed
Sponsored by: King Faisal Specialist Hospital & Research Center
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 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.
Clinical Details
Official title: The Placebo Effect May Involve Modulating Drug Bioavailability
Study design: Allocation: Randomized, Endpoint Classification: Pharmacokinetics Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Outcomes Assessor)
Primary outcome: Plasma half life
Secondary outcome: Area under the curveTmax Cmax
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.
Eligibility
Minimum age: 18 Years.
Maximum age: 60 Years.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- 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.
Exclusion Criteria:
- 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.
Locations and Contacts
King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia
Additional Information
Starting date: February 2012
Last updated: April 8, 2013
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