Charles Brown, MD and Paul J. Christo, MD
After injuring his back from lifting a piece of furniture, James, a 42-year-old man, is urged to take a multivitamin by his primary care doctor following a clinic appointment. Although the patient does not believe that the multivitamin will help, he reports a 50% pain relief in his follow-up visit 4 weeks later. The patient attributes this reduction to the multivitamin.
What could be the best possible explanation for the pain reduction?
The decrease in pain was likely due to the natural history of lower back pain: within 4-6 weeks, the symptoms from acute-onset back pain often resolve spontaneously. The perceived "placebo effect" accounts for improvements due to the natural history of the disease. The true placebo effect is the specific difference in effect observed in a trial of multivitamins for back pain patients, with some patients taking no medication and some patients taking multivitamins. This would control for any resolution of symptoms due to disease improvement. The specific therapeutic effect of the drug did not account for the observed degree of pain relief, since there is little evidence or biologic plausibility that vitamins could decrease back pain in such a short time.
Which theory ofplacebo action would best explain any pain reliefthat he experiences due to the placebo effect?
The cognitive theory of the placebo effect states that the expectations of the patient play an important role in the efficacy of the placebo, which is applicable to James. The conditioning theory would be applicable if he had previously experienced success with neuraxial blocks and subsequently responded favorably to the current procedure because of his previous successes. The endogenous opioid theory could explain his pain relief, but it is not the best answer.
Several weeks later, James develops postherpetic neuralgia and is prescribed a lido-caine patch. He is now complaining of nausea and vomiting, in addition to a moderate fatigue.
Which effect would best describe his symptoms?
The patient is suffering from a nocebo effect from the lidocaine patch: these symptoms are probably not related to the specific pharmaceutical action of the lidocaine patch itself. If these effects helped to decrease his pain, the effects would be considered specific therapeutic drug effects or placebo effects. However, since the effects are undesirable, they are either side effects from the medication (not a choice) or nocebo effects.
Ten years later, James develops hypertension and stable angina which are well controlled with lisinopril and metoprolol and sees you regularly to manage his conditions. He would like you to consider him for a placebo-controlled clinical trial for angina. When he is not compliant with his medication regimen, his anginal symptoms escalate. As part of the trial, he would need to stop his current medication regimen.
Which consideration would make it unethical for James to participate in the trial? When conducting a placebo-controlled trial, it is important to ensure that several ethical considerations are fulfilled. In this case, the patient suffers from unstable angina when his medications are discontinued. Therefore, the risk to the patient would be high, and enrolling him in placebo-controlled trial and discontinuing his medications would not be ethical. Clearly, there is a scientific rationale for improving the care of angina, and there is nothing in the vignette to suggest that the patient could not be monitored closely or would not be able to give informed consent.
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