Interaction Between Drug and Placebo Effect:Randomized Placebo Controlled Trials May Not be Accurate in Determining Drug Effect Size
|ClinicalTrials.gov Identifier: NCT01501591|
Recruitment Status : Completed
First Posted : December 29, 2011
Last Update Posted : March 3, 2017
|Condition or disease||Intervention/treatment|
|Placebo Effect Placebo Drug Interaction||Drug: Hydroxizine Other: Placebo Drug: hydroxyzine/placebo|
The total effect of a medication is the sum of its drug effect, placebo effect (meaning response of placebo), and their possible interaction. Current interpretation of the results of clinical trials (the gold standard in evidence based medicine) assumes no such interaction. Using a novel cross-over balanced placebo design and caffeine as a model drug we have recently shown that a negative interaction does exist; suggesting that the size of drug effect as currently measured by clinical trials may not be accurate. Due to the novelty of the findings and their important clinical practice and research implications, they need to be confirmed using another drug; and the size of drug effect measured using the novel design need to be directly compared to that measured using conventional clinical trial design.
A cross-over balanced placebo plus randomized placebo-controlled clinical trial design.
480 adults will be double-blindly randomized to three groups: first generation H-1 receptor antagonist- hydroxyzine (25 mg), placebo, or hydroxyzine+placebo group. The first two groups will receive the assigned intervention described by the investigators as hydroxyzine or placebo, in a randomized crossover design. The third group will receive hydroxyzine and placebo in a randomized double-blind placebo-controled crossover design. Group assignment will be concealed from volunteers and recruiters. Data collectors will be blinded to group assignment and intervention assignment. Volunteers will be partially deceived to the intervention assignment in the first two groups and blinded in the third group. The interventions to the third group will be also administered blindly. Serum hydroxyzine levels will be determined 3 hours post intervention from all volunteers to verify compliance and help maintain deception/blinding. The results of the study are expected to further our understanding of a widely used medical intervention, i.e., placebo, and help assess the appropriateness of randomized clinical trials in determining the size of drug effect.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||480 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Triple (Participant, Care Provider, Outcomes Assessor)|
|Primary Purpose:||Basic Science|
|Official Title:||Interaction Between Drug and Placebo Effect:Randomized Placebo Controlled Trials May Not be Accurate in Determining Drug Effect Size|
|Study Start Date :||November 2012|
|Primary Completion Date :||October 2015|
|Study Completion Date :||October 2015|
This group will receive a first generation H-1 receptor antagonist, hydroxyzine (25 mg) twice on two days; on one day described by the investigator as hydroxyzine and on the other day described by the investigator as placebo, in a randomized balanced crossover design.
25 mg orally, one time on two different days, 72 hours apart
This group will receive a placebo twice on two days; on one day described by the investigator as hydroxyzine and on the other day described by the investigator as placebo, in a randomized balanced crossover design.
Matching placebo once on two different days, 72 hours apart.
This group will receive hydroxyzine and placebo in a randomized double-blind placebo-controled crossover design.
25 mg hydroxyzine or placebo once on two different days, 72 hours apart
- Area-under-the-curve for drowsiness [ Time Frame: seven hours ]Seven-hour-area-under-the-curve of drowsiness on 100 mm visual analog scales will be determined
- Area-under-the-curve for dryness of the mouth [ Time Frame: seven hours ]Seven-hour-area-under-the-curve of dryness of the mouth on 100 mm visual analog scales will be determined
- Mean percent of time of reporting drowsiness on a dichotomous scale. [ Time Frame: seven hours ]Mean percent of time of reporting drowsiness on a dichotomous scale will also be determined.
- Mean percent of time of reporting dryness of mouth [ Time Frame: seven hours ]Mean percent of time of reporting dryness of mouth on a dichotomous scale will also be determined.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01501591
|King Faisal Specialist Hospital & research Center|
|Riyadh, Saudi Arabia, 11211|