Clinical trial NCT00426010: Measuring Placebo Effect by Elimination and Investigating Mechanism of Action
Official title: Measuring Placebo Effect by Elimination and Investigating Its Mechanism of Action
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Placebo Effect
Placebo Mechanisms of Action
Keywords: Placebo effect
Caffeine
Systolic BP
VAS
Lead sponsor: King Faisal Specialist Hospital & Research Center
Sponsor class: OTHER
Collaborators: name: King AbdulAziz City for Science and Technology
First posted: 2007-01-24
Enrollment: 180
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: We propose to measure the effect of placebo by elimination as well as by a "balanced placebo" design, determine its interaction with active drug, and explore whether placebo exerts part of its effect at the pharmacokinetics level.

Detailed description: Placebos have been in use for centuries in medical practice. However, there is continued controversy regarding their effectiveness and mechanisms of action.

The results of the study are expected to further our understanding of a widely used medical intervention, i.e., placebo, and of how to maximize its potential beneficial effect. It will also help assess the appropriateness of measuring the placebo effect by elimination, which has important ethical implications in relation to the design of randomized clinical trials.

Comparison: caffeine vs placebo. Dependent variables:4 hours area under the curve (AUC) of pharmacodynamics endpoints as well as pharmacokinetics endpoints in a subgroup.

Eligibility criteria: Inclusion Criteria:

* Males and nonpregnant females 18 and 40 years of age with at least high school education.

Exclusion criteria:

* Include evidence of clinically relevant deviation from normal health (such that it may affect the endpoints, make the ingestion of caffeine dangerous, or affect the pharmacokinetics/pharmacodynamics of caffeine),
* Pregnancy,
* Poor venous access,
* Hypertension (more than 140/90),
* Heart disease,
* History of panic attacks,
* Average daily caffeine consumption of more than 300 or less than 100 mg,
* Smoking,
* Alcohol abuse,
* Taking any medication other than birth control bills (including over-the-counter drugs) within one week from starting the study,
* Hypersensitivity to caffeine or related compounds,
* Hemoglobin of less than 13 gm/L, and recent (one week) acute illness

Primary outcomes:
measure: 4 hours area under the curve (AUC) of peripheral systolic blood pressure
timeFrame: 4 hours
measure: 4 hours area under the curve (AUC) of energy level measured by Visual Analogue Scales.
timeFrame: 4 hours
measure: 4 hours area under the curve (AUC) of alertness level measured by Visual Analogue Scales.
timeFrame: 4 hours
measure: 4 hours area under the curve (AUC) of nausea measured by Visual Analogue Scales.
timeFrame: 4 hours
Secondary outcomes:
measure: Cmax of serum caffeine (in a subgroup)
timeFrame: 4 hours
measure: Tmax of serum caffeine (in a subgroup)
timeFrame: 4 hours
measure: t1/2 of serum caffeine (in a subgroup)
timeFrame: 14 hours
measure: AUC of serum caffeine (in a subgroup)
timeFrame: 14 hours
Other outcomes:
Locations:
city: Riyadh
country: Saudi Arabia
facility: Center for Clinical Studies & Empirical Ethics, KFSH & RC
Study officials:
affiliation: KFSH & RC, Riyadh
name: Muhammad M Hammami, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hammami MM, Al-Gaai EA, Alvi S, Hammami MB. Interaction between drug and placebo effects: a cross-over balanced placebo design trial. Trials. 2010 Nov 19;11:110. doi: 10.1186/1745-6215-11-110.