Cost effectiveness of tolvaptan

Amin and Meeran refer to the relative expense of tolvaptan, one of the new vasopressin 2 receptor antagonists.1 They suggest that it has little benefit over existing treatments but fail to mention that in the syndrome of inappropriate antidiuretic hormone hypersecretion, tolvaptan increases the rate of normalisation of hyponatraemia.2 Tolvaptan has recently been added to the formulary of Guy’s, King’s, and St Thomas’ hospitals because it speeds the recovery of disturbed sodium balance when used in conjunction with strict fluid restriction. One study found that it reduced mean length of hospital stay by 2.12 days.3 In this syndrome, the £74.68 (€84.84; $120) cost of one tolvaptan tablet brings the benefit of reduced length of stay and the cost saving of a hospital bed (hundred of pounds a day). This is especially important in acute neurosurgical units, where this type of metabolic disturbance is relatively common and the demand for hospital beds great.