Collaborative Review – Stone DiseaseMedical Therapy to Facilitate the Passage of Stones: What Is the Evidence?
Introduction
The simplest approach to medical expulsion therapy (MET) would be a high fluid intake to increase the hydrostatic pressure proximal to the stone or to increase the volume of urine transported through the ureter, thereby increasing peristaltic activity. The drawback is that it cannot easily be predicted to what extent a ureteral stone obstructs urine flow. In the case of partial or incomplete obstruction, constantly or intermittently, high diuresis is likely to counteract the passage of the stone and cause more pain. A systematic review evaluating the effect of fluids and diuretics found no credible evidence supporting a diuretic approach in terms of pain relief and stone expulsion [1].
An improved understanding of ureteral physiology has led to anti-inflammatory and anti-oedematous treatment with nonsteroidal anti-inflammatory drugs (NSAID) such as nonselective cyclooxygenase (COX) inhibitors or COX-2 inhibitors, decreasing ureteral contractions [2]. However, they appeared not to affect stone expulsion rates in double-blind, placebo-controlled trials [3], [4].
Antimuscarinics might relax genitourinary smooth muscle, reducing colic pain [5]. However, a randomised, placebo-controlled trial determining whether N-butylscopolamine (Buscopan) reduces the amount of opioid analgesia required in renal colic demonstrated no favourable effect [6]. Additionally, N-butylscopolamine failed to significantly reduce renal pelvic pressure [7] and was less effective than dipyrone. So far, those regimens have failed to demonstrate an increase in stone expulsion rates.
Phosphodiesterase (PDE) regulates intracellular cyclic nucleotide turnover, influencing smooth muscle tension. Recently, the ureteral smooth muscle relaxing effects of PDE type 4 inhibitor (PDE4-I) and PDE type 5 inhibitor (PDE5-I) in vitro have been reported. Results were similar to those reported for tamsulosin, suggesting the potential for using PDE inhibitors in the treatment of ureteral colic [8], [9], but so far, their potential role in expulsion therapy has to be assessed in controlled studies.
Use of corticosteroids with anti-inflammatory action has been reported to facilitate stone expulsion [10]. So far, one randomised trial (published as an abstract) supports a significant effect of methylprednisolone on distal ureteral stone expulsion [11]. However, publications in peer-reviewed journals are necessary. So far, there is no further evidence confirming whether corticosteroids alone are capable of facilitating stone expulsion.
The calcium channel blockers nifedipine and verapamil inhibit endogenous prostaglandin synthesis and calcium influx, reducing spontaneous rhythmic contractions of the human ureter [12]. Similarly, α-blockers inhibit contractions of ureteral musculature, reduce basal tone, and decrease peristaltic frequency and colic pain, possibly facilitating ureteral stone expulsion and suggesting a beneficial effect for MET. This conclusion is further supported by a pilot study investigating the in vivo effect of nifedipine and tamsulosin on ureteral contraction frequency, pressure, and velocity using a ureteric pressure transducer in humans. Both drugs allowed peristalsis to continue, which is important for successful stone expulsion [13]. So far, the most promising drugs studied for MET are α-blockers and calcium channel blockers, mirrored by an increasing study activity and providing the rationale for this systematic review.
Section snippets
Search strategy
The US National Library of Medicine's life science database (Medline), Embase, the Cochrane Central Register of Controlled Trials, and the Cochrane Database for Systematic Reviews were searched through 31 December 2008 without time limit. The Medline search employed a search strategy that included Medical Subject Headings (MeSH) and free-text protocols. The terms urolithiasis and lithotripsy were used in conjunction with calcium-channel-blocker, adrenergic alpha-antagonists, prostaglandin
Quality assessment of studies incorporated in the final analysis
Jadad scores ranged from 0 to 5, with a median score of 2. Five double-blind studies were reported (Table 1). Allocation concealment was rarely assessable (level A was applicable to only one trial [17]) and therefore could not be integrated into the quality assessment.
α-Blocker therapy
Twenty-nine studies [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45] were analysed, including 2419
Conclusions
Evidence suggests that MET using nifedipine, tamsulosin, doxazosin, or terazosin can be suggested as treatment for ureteral stones owing to its expulsive efficacy, pain reduction, and safety profile. No recommendation can be made concerning the superiority of either nifedipine or α-blockers. Although a class effect of α-blockers can be anticipated, no recommendation can be made concerning alfuzosin. There is some evidence that a combination of α-blockers and corticosteroids might be more
References (70)
- et al.
Does methylprednisolone acetate increase the success rate of medical therapy for passing distal ureteral stones?
Eur Urol Suppl
(2005) - et al.
Assessing the quality of reports of randomized clinical trials: is blinding necessary?
Control Clin Trials
(1996) - et al.
Meta-analysis in clinical trials
Control Clin Trials
(1986) - et al.
Alfuzosin stone expulsion therapy for distal ureteral calculi: a double-blind, placebo controlled study
J Urol
(2008) - et al.
Efficacy of tamsulosin in the medical management of juxtavesical ureteral stones
J Urol
(2003) - et al.
Nifedipine versus tamsulosin for the management of lower ureteral stones
J Urol
(2004) - et al.
Alpha-1 receptor blocking therapy for lower ureteral stones: a randomized prospective trial [abstract A1152]
J Urol
(2004) - et al.
Does tamsulosin enhance lower ureteral stone clearance with or without shock wave lithotripsy?
Urology
(2004) - et al.
The comparison and efficacy of 3 different α1-adrenergic blocker for distal ureteral stones
J Urol
(2005) - et al.
Randomized trial of the efficacy of tamsulosin, nifedipine and phloroglucinol in medical expulsive therapy for distal ureteral calculi
J Urol
(2005)