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Trial Design: Pain Sections
Author Bio
Introduction
Currently selected section: Placebo Effects
Single Dose Trials
Repeated Dose Trials
Explanatory Versus Pragmatic
Dose-Response
Parallel Group Versus Crossover
Conclusion
 

 

Chapter 1: Clinical Trials of Pain Treatment: Placebo Effects: Problem 2.2
 
         What is your interpretation?

You answered:


Selection D
  The study should be replicated with the two treatment groups being Compound G or an active placebo, a low dose of a benzodiazepine to mimic the sedative side effects of Compound G.

CORRECT (in my opinion)

Some researchers favor the use of such "active placebos" (Greenberg and Fisher, 1994), and I tend to agree. The finding that a new drug relieves pain better than another drug that produces similar side effects is quite convincing, particularly when accompanied by evidence that the blinding has remained effective and is a protection against false positives caused by drug side effects. Others argue against the use of active placebos. One argument is that it is unethical to expose patients to the adverse effects of the active placebo without expectation of benefit. That argument is largely countered by using doses just large enough to produce mild side effects in most patients. A more serious concern is that if the active placebo has some unexpected effect of worsening pain, this can again produce a false positive result for the putative analgesic under evaluation. The investigator should examine animal and human studies of pain to ascertain that the proposed active placebo does not worsen or improve pain.

It is not clear whether one needs to exactly match the magnitude of the side effects of the two treatments to eliminate this bias. The study illustrated in Figure 2.2 suggested that most of the side-effect induced placebo response occurs with the detection of the first mild symptom, but further research is needed.

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