What is the efficacy of MET in the treatment of nephrolithiasis?

Updated: Jun 21, 2018
  • Author: Chirag N Dave, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Multiple prospective randomized controlled studies in the urology literature have demonstrated that patients treated with oral alpha-blockers have an increased rate of spontaneous stone passage and a decreased time to stone passage. [55, 56, 57] The best studied of these is tamsulosin, 0.4 mg administered daily.

A systematic review by Singh et al found that MET using either alpha antagonists or calcium channel blockers augmented the stone expulsion rate for moderately sized distal ureteral stones. Adverse effects were noted in 4% of those taking alpha antagonists and in 15.2% of those taking calcium channel blockers. [64]

A systematic review by Beach et al found that MET with alpha antagonists for 28 days increased the rate of stone passage, decreased the time to stone passage, and decreased the rates of hospitalization and ureteroscopy, with minimal adverse effects. [65]

Not all data support MET. A randomized study of 77 ED patients with ureterolithiasis found no benefit to a 14-day course of tamsulosin, though the study group was small and the average stone size was 3.6 mm, making spontaneous passage without MET highly likely. [66] Similarly, a prospective, placebo-controlled trial by Pickard et al in 1167 adults with ureteral stones found that neither tamsulosin nor nifedipine decreased the need for further treatment to achieve stone clearance in 4 weeks. [67]

However, Hollingsworth et al propose that the findings of Pickard et al may be largely due to the high rate of spontaneous stone passage in the control group, perhaps because a large proportion of patients had smaller stones. In a systematic review and meta-analysis, these authors concluded that alpha-blockers help facilitate the passage of larger ureteric stones. They recommend considering a course of an alpha-blocker for patients with ureteral colic, unless it is medically contraindicated. [51]

Hollingsworth et al found that overall, passage of larger stones was 57% more likely in patients treated with an alpha-blocker compared with controls (risk ratio 1.57); the likelihood of stone passage increased by 9.8% with every 1 mm increase in stone size. The effect of alpha-blockers was independent of stone location within the ureter. They estimated that four patients would need treatment for one patient to realize benefit from alpha-blockers. Adverse effects associated with alpha-blocker use were relatively infrequent and were not severe. [67]

Additional evidence that alpha-blockers do not expedite the passage of ureteral stones emerged from a randomized clinical trial of 512 adult emergency department patients who presented with renal colic owing to ureteral stones smaller than 9 mm. In this study, the proportion of patients who achieved ureteral stone expulsion by 28 days was 50% with tamsulosin versus 47% with placebo, a nonsignificant difference. [68]

MET with alpha-blockers also appears to improve the results of ESWL (see Surgical Care) inasmuch as the stone fragments resulting from treatment appear to clear the system more effectively.

Analgesic therapy combined with MET dramatically improves the passage of stones, addresses pain, and reduces the need for surgical treatment. Ibuprofen can be substituted for the ketorolac tablets recommended in the original studies. Fewer complications with ibuprofen occur while maintaining efficacy for pain relief. An oral narcotic (eg, oxycodone/acetaminophen) is used as needed to control breakthrough pain.


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