Effect of tropisetron versus placebo on cold-induced oxygen consumption and shivering in male volunteers

Abstract

In a prospective, randomized, cross-over, placebo-controlled study in healthy male volunteers, we tested the effect of the 5-HT 3 antagonist tropisetron on cold-induced oxygen consumption and shivering. Cooling was performed by intravenous infusion of isotonic salt solution at 4 °C. Whole-body oxygen consumption (VO 2) was measured with a metabolic monitor. Shivering was qualitatively assessed. When the shivering score evaluated “2” (intense shivering), 5 mg tropisetron or NaCl 0.9% was injected and repeated if necessary, to completely stop shivering. The VO 2 before shivering (178±9 ml/min/m 2) rose significantly during shivering (291±21 ml/min/m 2). 5 mg of tropisetron in 2 volunteers and 10 mg in 3 volunteers stopped shivering but it returned (grade 0–1). The VO 2 decreased significantly (209±17 ml/min/m 2). Placebo had no effect. Tropisetron reduced cold-induced VO 2 and intensity of hypothermic shivering. That an additional dose of tropisetron could not stop the shivering totally may indicate that the effect of tropisetron is not dose dependent.