Efficacy and Safety of Naftopidil in the Medical Expulsion Therapy for Distal Ureteral Stone: A Systematic Review and Meta-Analysis

The affinity and selectivity of α-adrenoceptor antagonists, antidepressants and antipsychotics for the human α2A, α2B, and α2C-adrenoceptors and comparison with human α1 and β-adrenoceptors

α2-Adrenoceptors, subdivided into α2A, α2B, and α2C subtypes and expressed in heart, blood vessels, kidney, platelets and brain, are important for blood pressure, sedation, analgesia, and platelet aggregation. Brain α2C-adrenoceptor blockade has also been suggested to be beneficial for antipsychotic action. However, comparing α2-adrenoceptor subtype affinity is difficult due to significant species and methodology differences in published studies. Here, ³ H-rauwolscine whole cell binding was used to determine the affinity and selectivity of 99 α-antagonists (including antidepressants and antipsychotics) in CHO cells expressing human α2A, α2B, or α2C-adrenoceptors, using an identical method to β and α1-adrenoceptor measurements, thus allowing direct human receptor comparisons. Yohimbine, RX821002, RS79948, and atipamezole are high affinity non-selective α2-antagonists. BRL44408 was the most α2A-selective antagonist, although its α1A-affinity (81 nM) is only 9-fold greater than its α2C-affinity. MK-912 is the highest-affinity, most α2C-selective antagonist (0.15 nM α2C-affinity) although its α2C-selectivity is only 13-fold greater than at α2A. There are no truely α2B-selective antagonists. A few α-ligands with significant β-affinity were detected, for example, naftopidil where its clinical α1A-affinity is only 3-fold greater than off-target β2-affinity. Antidepressants (except mirtazapine) and first-generation antipsychotics have higher α1A than α2-adrenoceptor affinity but poor β-affinity. Second-generation antipsychotics varied widely in their α2-adrenoceptor affinity. Risperidone (9 nM) and paliperidone (14 nM) have the highest α2C-adrenoceptor affinity however this is only 5-fold selective over α2A, and both have a higher affinity for α1A (2 nM and 4 nM, respectively). So, despite a century of yohimbine use, and decades of α2-subtype studies, there remains plenty of scope to develop α2-subtype selective antagonists.

Efficacy of Naftopidil as a Medical Expulsive Therapy in Japanese Men With Ureteral Stones: A Prospective Randomized Controlled Study

Background

Naftopidil combined with an antispasmodic agent and a supplement that facilitates stone expulsion has reportedly produced an increased rate of ureteral stone expulsion. A randomized controlled study was conducted to determine the efficacy of naftopidil as a medical expulsive therapy for male patients with ureteral stones.

Methods

Male patients (n = 500) with stones from the upper to the lower ureter were randomized to one of four groups and followed for 1 month to assess spontaneous passage of stones. The control group received only analgesics. The other three groups received daily doses of 240 mg flopropione, an antispasmodic agent and 1,350 mg extract of Quercus salicina Blume/Quercus stenophylla Makino (QS), a supplement that facilitates stone expulsion; 50 mg naftopidil; or 50 mg naftopidil in combination with 240 mg flopropione and 1,350 mg QS. Stone expulsion and characteristics were evaluated by urinalysis; kidney, ureter and bladder X-ray; ultrasound; and computed tomography.

Results

The probability of expulsion of ureteral stones < 6 mm increased 1.570-fold (95% confidence interval (CI): 1.039 - 2.374, P < 0.05) with naftopidil compared to control; the probability of expulsion of a lower ureteral stone < 6 mm increased 1.778-fold (95% CI: 1.066 - 2.965, P < 0.05) with naftopidil compared to control. None of the stones > 6 mm spontaneously passed.

Conclusions

For relatively small ureteral stones < 6 mm, analgesic treatment combined with naftopidil would be the first choice. However, for relatively large ureteral stones > 6 mm, it appears that analgesia is sufficient for initial treatment of ureteral stone.

Ureteral wall thickness as a significant factor in predicting spontaneous passage of ureteral stones of ≤ 10 mm: a preliminary report

PURPOSE

To evaluate the clinical significance of ureteral wall thickness (UWT) for predicting spontaneous passage (SP) of uncomplicated ureteral stones of ≤ 10 mm.

METHODS

We retrospectively reviewed 418 patients with a diagnosis of uncomplicated ureteral stones who presented to Kori Hospital from 2011 to 2018. The maximum stone diameter and UWT at the stone site were measured from axial computed tomography images. Clinical predictors of 4-week SP were assessed using univariate and multivariate analyses. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the accuracy of factors in predicting SP of ureteral stones.

RESULTS

Of the 418 patients, 202 (48.3%) spontaneously passed their stones within 4 weeks of their initial visit. Multivariate analysis showed that stone location, stone size, and UWT (odds ratio, 0.40; P < 0.001) were independent predictors of 4-week SP. ROC analysis showed that 2.71 mm was the optimal cut-off value for UWT, with a predictive accuracy of 0.83. Low UWT had a significantly higher 4-week SP rate than high UWT (76.4% vs. 14.7%, respectively; P < 0.001). In addition, high UWT was associated with a higher risk of stone-related complications within 4 weeks compared with low UWT (16.4% vs. 7.2%, respectively; P = 0.0044).

CONCLUSIONS

UWT can serve as a potential predictive factor for 4-week SP and may help physicians to select patients who require immediate interventions among those with ≤ 10-mm ureteral stones.