Context and objective: Guaraná (Paullinia cupana) has been used medicinally for centuries. The aim of this study is evaluate the effectiveness of guaraná in the treatment of postradiation depression and fatigue.
Design and setting: This study had a double-blind randomized design with crossover between experimental arms, at Faculdade de Medicina da Fundação do ABC.
Methods: We conducted a randomized double-blind crossover trial with 36 patients with breast cancer undergoing adjuvant radiation therapy. We randomized patients to either guaraná 75 mg daily p.o. or to placebo. Patients were switched to the other experimental arm at the middle of the radiation treatment, which consisted of 28 daily fractions of 180 cGy. Evaluations were conducted at the beginning, at the middle, and at the end of radiation therapy.
Results: We were unable to show any statistically significant differences between the guaraná and the placebo-treated group with any of the measured scores. Also, within the same group, we did not see any statistically significant associations during either the guaraná- or placebo-treated periods with any of the aforementioned measures.
Conclusions: We were unable to show that patients with breast cancer undergoing radiation therapy derive any advantage with guaraná over placebo for both fatigue and depressive symptoms.