Efeitos placebo, nocebo e lessebo na farmacoterapia: conceitos ampliados e reflexões sobre possíveis impactos na odontologia

Abstract

The drug response is multifactorial and may include placebo, nocebo, and lessebo effects. Thus, the objective of the present work was to promote reflections, through a narrative review, about the concepts, models and factors involved in the placebo, nocebo and lessebo effects in pharmacotherapy, including possible impacts on dental conduct. It was seen that the literature is vast in the sense of pointing to a chain of favorable and unfavorable events, parallel to the expected pharmacological effects, during the use of drugs by the patient. In the context of clinical practice, the placebo effect can be understood as part of the favorable therapeutic response, which is not attributable to the properties of the active ingredients. On the other hand, the nocebo effect is seen as the opposite of the placebo effect, and comprises the undesirable effects that go beyond the action of pharmacologically active substances, which can lead to aggravation of symptoms and impairment in the acquisition and maintenance of treatment. The lessebo effect is a recent, well-defined term for a clinical trial. Expanding to the clinical context, lessebo effect can be understood as the reduction of the magnitude of the effect of an active substance, due to the possibility of receiving an intervention with supposedly little or no efficacy. Classical conditioning and conscious expectations models are used to try to explain such effects. Among the factors associated with the occurrence of placebo-nocebo-lessebo effects are: past experiences with the use of medications, the prescriber-patient relationship, social transmission, among others. During the occurrence of each of these effects, the involvement of distinct neurophysiological mechanisms, such as the opioid and dopaminergic systems, has already been demonstrated. In addition, clinical intervention strategies are suggested for the health professional in order to maximize the positive effects and minimize the negative effects during drug therapy, which include: giving the patient the chance to ask questions and raise their concerns about the treatment, investigate experiences with pharmacotherapy, investigate cure expectations, and present realistic effects of interventions. In conclusion, placebo, nocebo and lessebo effects can impact clinical practice, and knowledge on the part of dental students and professionals is essential. Strategies can be adopted to increase the success rate during pharmacotherapy.