Fluoxetine impairs muscular strength, power and endurance performance particularly when it is co-ingested with caffeine:: a case study

Introduction: Fluoxetine is a recurrent pharmacotherapy for depression used in athletes since it does not seem to impair sports performance. Some athletes combine this drug with caffeine, however, the combined effect of both drugs remains to be elucidated. This study aimed to explore the combined effect of fluoxetine and caffeine on muscular strength, power, and endurance performance.Methodology: In this case study, a resistance-trained female was recruited to complete four randomized experimental conditions: a) placebo (PLA); b) placebo and fluoxetine (PLA+FLU); c) caffeine (CAF); d) caffeine and fluoxetine (CAF+FLU). The participant was provided with 20 mg/day of fluoxetine and 3 mg/kg of body mass of caffeine or maltodextrin (placebo) 60 minutes after performing the tests. The participant performed for bench press and back squat exercises a muscular strength and power test at 25%, 50%, 75% and 90%1-repetition-maximum (1RM), followed by a muscular endurance assessment at 65% and 85%1RM.Results: CAF+FLU reduced mean velocity and power output in both exercises at 75% and 90%1RM in muscular strength and power tests and at 85%1RM in the muscular endurance test. While PLA+FLU and CAF+FLU administration reduced peak velocity and mean and peak power output at 25%1RM in the muscular strength and power test and at 65%1RM in the muscular endurance test.Conclusions: Fluoxetine may counteract the ergogenic effect of caffeine impairing muscular strength, power and endurance performance. Therefore, although further studies are needed, athletes diagnosed with depression on fluoxetine treatment should reconsider caffeine consumption as a nutritional supplement to enhance performance Introducción: La fluoxetina es un fármaco utilizado para la depresión especialmente en deportistas ya que parece no alterar el rendimiento deportivo. Algunos atletas combinan este fármaco con cafeína, sin embargo, el efecto combinado de ambas drogas se desconoce. Este estudio tuvo por objetivo explorar el efecto combinado de fluoxetina y cafeína sobre el rendimiento de fuerza, potencia y resistencia muscular. Metodología: En este estudio de caso, una mujer entrenada en fuerza realizó cuatro condiciones experimentales: a) placebo (PLA); b) placebo y fluoxetina (PLA+FLU); c) cafeina (CAF); d) cafeína y fluoxetina (CAF+FLU). La participante ingirió 20 mg/día de fluoxetina y 3 g/kg de masa corporal de cafeína o placebo (maltodextrina), 60 minutos antes de realizar los test. La participante reali