Current pharmacotherapy of nocturia

Aging increases the expression of vasopressin receptors in both the kidney and urinary bladder

AIMS

The goal of this study was to determine whether aging effects the expression of V_1a and V₂ vasopressin receptors in the urinary bladder mucosa (UBM) and kidney.

METHODS

UBM and kidneys were obtained from young (3 months-of-age) and old (25-30 months-of-age) female Fisher 344 rats. Tissue samples were analyzed by western blotting for V_1a and V₂ receptor expression, and rat plasma levels of vasopressin levels were measured by ELISA.

RESULTS

V_1a and V₂ receptors were detected in both the UBM and kidneys. Aging significantly (P < 0.05) increased the expression of V₂ receptors by 2.80 ± 0.52 and 6.52 ± 1.24-fold in the UBM and kidneys, respectively. Aging also increased V_1a receptor expression in the kidneys (5.52 ± 1.05 fold; P < 0.05), but not in the UBM. To the best of our knowledge, because this is the first detection of V₂ receptors in the mammalian bladder mucosa, we also probed human UBM for V₂ receptors and observed high expression in human UBM. Unlike V_1a and V₂ receptors, aging had only a minor effect on plasma vasopressin levels (8% increase).

CONCLUSIONS

V₂ receptors are substantially increased in the aging UBM. The role of these receptors in UBM is as yet undefined, but given their presence and action in the kidneys, the possible effect of these receptors in free water regulation should be considered. The large age-related increase in the expression of V₂ receptors in both the UBM and kidney may contribute to the effectiveness of desmopressin in age-related nocturia.

Tolterodine treatment of women with overactive bladder syndrome: Comparison of night-time and daytime dosing for nocturia

AIM

We aimed to clarify the impact of night-time dosing with tolterodine extended release (ER) on nocturia.

METHODS

The bladder diaries, urodynamic studies, and medical records of female patients with overactive bladder syndrome who were diagnosed between January 2005 and December 2015, and treated with tolterodine ER 4 mg once per day (night-time or daytime dosing) for 12 weeks in the urogynecology outpatient clinics of two tertiary referral centers were reviewed retrospectively.

RESULTS

A total of 72 female patients were reviewed. Thirty-six patients were in the daytime dosing group, and the other 36 patients were in the night-time dosing group. In the daytime dosing group, a decrease in the volume of fluid intake was found at 06.00-12.00, 12.00-18.00, and 18.00-24.00 hours, and a decrease in total voided volume was found at 12.00-18.00, 18.00-24.00, and 24.00-06.00 hours with a between-group difference at 18.00-24.00 hours (coefficient = 542 mL, P = 0.01). In the night-time dosing group, an increase in voided volume per micturition was found at 06.00-12.00 and 24.00-06.00 hours with a between-group difference at 24.00-6.00 hours (coefficient = 92 mL, P = 0.003) compared with the daytime dosing group. Nonetheless, pre-treatment proportions of nocturnal polyuria did not differ from post-treatment proportions (night-time: 20% vs 20%, P = 1.00; daytime: 48% vs 42%, P = 0.48). Decreases in the number of voiding and urgency episodes at nearly all time periods and increases in the volumes at strong desire to void were also found in both groups.

CONCLUSION

Night-time dosing of tolterodine ER may benefit female patients suffering from nocturia due to a greater voided volume per micturition at midnight.