An estimated 13 percent of men and 7 percent of women experience urinary stones. Within five years of the first episode, about one half of patients have a recurrence. In addition to personal pain and distress, direct health care costs for urolithiasis in the United States exceed $2 billion annually. Between 71 and 98 percent of small stones (5 mm or less in diameter) in the distal urinary tract pass without surgery or lithotripsy. However, large stones and those causing urinary obstruction require removal. Hollingsworth and colleagues examined medical therapies to facilitate passage of urinary stones. Their focus was to inform physicians who initially treat patients with urolithiasis (e.g., family physicians, emergency department physicians) about the possible effectiveness of treatment with calcium channel blockers or alpha-adrenergic blocking agents.
The authors searched for randomized controlled studies of urolithiasis in which calcium channel blockers or alpha-adrenergic blocking agents were the principal therapies for urolithiasis. Studies of other medications or studies in which medications were used as adjuncts to invasive therapy were excluded from the analysis. The search included several electronic databases, abstracts from major urologic conferences, and contacts with drug manufacturers to identify unpublished trials. Two reviewers independently extracted data, and differences were resolved by consensus. The primary end point was the proportion of patients who passed stones.
Nine clinical trials (693 total patients) were included in the meta-analysis. All trials involved outpatients, and the mean age ranged from 34 to 46 years. The mean stone diameter was 3.9 to 7.8 mm. The treatment duration ranged from seven days to six weeks, and follow-up ranged from 15 to 48 days. In three trials, patients received corticosteroids with the calcium channel blocker nifedipine (Procardia). In seven trials, patients received nonsteroidal anti-inflammatory drugs with specific therapy for the stones. In the five studies of alpha blockers, 53 to 90 percent of patients in the treatment group passed stones, compared with 20 to 46 percent in the control group. The three studies combining alpha blockers with steroids had higher rates of stone passage in the treatment group (85 to 100 percent). Similarly, in the three studies of calcium channel blockers, 75 to 91 percent of patients in the treatment group passed stones compared with 46 to 64 percent in the control group.
Although the studies were heterogeneous, therefore limiting the meta-analysis, the authors calculate that patients receiving either class of medication had a 65 percent greater likelihood of stone passage than those in the control group. The pooled risk ratio was 1.54 for alpha blockers and 1.90 for calcium channel blockers with steroids. The authors estimate a number needed to treat of four. In those studies that reported pain or use of analgesia, these factors also were reduced in patients treated with medical expulsive therapy. Another study reported reduced use of health services (e.g., emergency department visits, surgery for stone removal) and fewer days lost from work in patients treated with alpha blockers or calcium channel blockers. Adverse effects data were inconsistent, but hypotension and palpitations were associated with therapy in less than 4.2 percent of patients.
The authors conclude that patients treated with alpha blockers or calcium channel blockers have a better chance of passing a distal ureteral stone, and in a shorter amount of time, than those not treated. Treated patients also had reduced pain and use of medical services. Although high-quality randomized controlled trials are needed to confirm these findings, medical expulsive therapy could substantially benefit patients and reduce health care costs.