Year : 2009 | Volume
: 25 | Issue : 4 | Page : 559--560
Naftopidil as medical expulsive therapy for distal ureteral stone
Abhishek Jain1, HS Pahwa2, Apul Goel1,
1 Department of Urology, King George Medical University, Lucknow - 226 003, Uttar Pradesh, India
2 Department of Surgery, King George Medical University, Lucknow - 226 003, Uttar Pradesh, India
Department of Urology, King George Medical University, Lucknow - 226 003, Uttar Pradesh
|How to cite this article:|
Jain A, Pahwa H S, Goel A. Naftopidil as medical expulsive therapy for distal ureteral stone.Indian J Urol 2009;25:559-560
|How to cite this URL:|
Jain A, Pahwa H S, Goel A. Naftopidil as medical expulsive therapy for distal ureteral stone. Indian J Urol [serial online] 2009 [cited 2021 Oct 23 ];25:559-560
Available from: https://www.indianjurol.com/text.asp?2009/25/4/559/57898
Authors conducted a randomized controlled study from March 2006 to January 2007 to determine the role of naftopidil as medical expulsive therapy (MET) for distal ureteral stone. Sixty patients with unilateral distal ureteral stones were enrolled in this study. Diagnosis was made by ultrasonography and X-ray KUB primarily and CT scan or intravenous urogram if required. Patients with multiple stone, severe impacted stone, previous distal ureteral surgery, renal colic >24 h, urinary tract infection, pregnancy and systemic medical diseases were excluded from the study. Patients were then randomized into two groups. Group 1 served as control and underwent watchful waiting while group 2 received 50 mg naftopidil daily in the morning. There was no difference between the groups in patient age (mean age in group-1 37.8±10.2, group-2, 38.2±12.6 yrs; p=NS), sex (group-1, 26 male:4 female; group-2, 24 male:6 female, p=NS) and stone size (overall mean size=5.5 ± 1.2 mm). Results were studied in the form of stone expulsion rate, potential side effects of naftopidil, number of pain episode and requirement of analgesics during 14-days study period. Results shows that stone expulsion rate were significantly higher in naftopidil group (90% vs. 26.7%, p  There is a roughly linear relationship between stone size and likelihood of spontaneous passage and about 87, 72, 47, and 27% of stones measuring 1, 4, 7 and 10 mm on CT scan pass spontaneously.  Distal ureteral stones are managed either by URS or SWL and the reported success rates are approximately 97 and 74% respectively.  Alpha-1 blockers and calcium channel blockers are also used as MET for distal ureteral stones.
The rationale behind the use of alpha blockers is that stimulation of α1 receptors in the ureter causes increased ureteral peristalsis, smooth muscle tone and contractile force resulting in ureteral spasm and decreased ureteral urine flow. Thus blockade of α1 receptors causes inhibition of basal tone, reduces peristaltic amplitude and frequency, decreases intra-luminal pressure while increasing the rate of fluid transport. Alpha-1 blockers induce an increase in the intra-ureteral pressure gradient around the stone that helps in stone expulsion. 
As MET for distal ureteral stone, tamsulosin and nifedipine have been studied in doses of 0.4 mg and 30 mg daily respectively, for 14 to 28 days in various studies. Porpiglia et al. reported that expulsion rate was 43%, 80%, and 85% in control, nifedipine and tamsulosin group respectively, while the average expulsion time was 12 days in control group, 9.3 days in nifedipine group and 7.7 days in tamsulosin groups.  The reported side effect of nifedipine was hypotension and palpitations in 2.5-4.3% while 3.3-4.2% patients receiving tamsulosin had transient hypotension.
Alpha-1 receptors are present in the ureter and are maximally concentrated in the distal ureter. Three subtypes of α1 receptor have been described, namely, α1a, α1b , and α1d. Among these, α1d receptors have the highest density in distal ureter. Alpha 1d receptors are also present on detrusor muscle and spinal cord. In detrusor muscles α1d receptors are nearly two times than α1a receptor while α1b receptors are absent. Naftopidil, a specific α1d receptor antagonist, have 3 and 17 fold higher potency for α1d than α1a and α1b. Naftopidil is used in the treatment of BPH and nocturia in some countries like Japan due to its relieving effects on detrusor and spinal cord reflexes and the selective antagonistic activity of α1d adrenoreceptor.  However, the use of naftopidil in MET is first described in this study. Naftopidil have little side effects such as dizziness and asthenia in about 6.7% patients.
Further clinical trials are needed to compare the efficacy of naftopidil with tamsulosin as expulsive therapy for distal ureteral stones.
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