Successful treatment of congestive heart failure with concomitant administration of tolvaptan to enhance the effects of furosemide

Abstract Tolvaptan (TLV), which is an antagonist to the vasopressin V2 receptor, was approved by Japanese authorities for the treatment of “volume overload in heart failure when adequate response is not obtained with other diuretics (e.g. loop diuretics)”. An 82-year-old female Japanese patient was admitted to our hospital due to congestive heart failure (CHF) and exacerbation of type 2 chronic respiratory failure, which improved with ventilator support and treatment with furosemide; however, the CHF worsened again due to anemia and undernutrition. TLV (7.5 mg/day) was given. The free-water clearance value showed the efficacy of TLV; it was −0.04 before and 0.39 six hours after TLV administration. The administration of TLV was continued for five consecutive days, and the fractional excretion of sodium showed the efficacy of furosemide; it was 1.7% before and 5.2% five days after TLV administration. It is known that the long-term usage of loop diuretics causes tolerance because it promotes sodium re-absorption through the proximal renal tubules by activating the renin–angiotensin-aldosterone system. A patient with CHF was treated successfully by concomitant administration of TLV with furosemide. TLV worked both directly and indirectly; it promoted free-water filtration as its direct effect and sodium filtration as its indirect effect. Learning objective: Tolvaptan is a new type drug for heart failure that promotes water diuresis by selectively inhibiting the vasopressin V2 receptors in collecting tubules. Concomitant use of tolvaptan with loop diuretics, such as furosemide, enhances the diuretic action. The mechanism of enhanced diuretic action induced by the concomitant use of tolvaptan with loop diuretics not only promotes water diuresis, known as tolvaptan's primary function, but may also enhance natriuresis induced by loop diuretics.>