[Etiology of nocturia and clinical efficacy of naftopidil on nocturia in patients with benign prostatic hyperplasia--analysis of frequency volume charts].

The etiology of nocturia in 70 patients with benign prostatic hyperplasia (BPH) who had nocturia of two or more times were examined based on frequency volume charts (FVC). Nocturia was classified into four groups: nocturnal polyuria, low capacity, combined nocturia, and no evidence of abnormality. Nearly half of the cases had nocturnal polyuria only. A little under 70% of patients had associated nocturnal polyuria (nocturnal polyuria+combined nocturia). Naftopidil was administered for three months to the patients with BPH who had nocturia with a urinary frequency of two or more times. Clinical efficacy was evaluated in 32 patients based on FVC and naftopidil was shown to improve nocturia. The improvement in nocturia was determined by the increment in voided volume.