Two recent meta-analyses have reported the potential
role of α-blockers and calcium-channel blockers in MET.
Hollingsworth and co-workers [17] included nine randomized
controlled trials, which included 693 subjects, although
all but one trial had serious methodological flaws. Studied
interventions included the calcium-channel blocker nifedipine
and several different α-blockers whilst the comparative
control arms included placebo, other vasodilators, antispasmolytics,
anticholinergic therapy and corticosteroids.
Overall spontaneous stone passage occurred in 47% of the
control group whilst patients given MET with either drug
were 65% more likely to pass the stone, with an absolute
risk reduction of 31%. Three studies reported a head-tohead
comparison between nifedipine and α-blockers. Two
of these studies did not report any statistically significant
difference in stone passage rates between the two drugs,
whilst one study found the α-blocker to be superior to nifedipine,
with a relative risk reduction of 26%.