Effect of verapamil on urinary stone-forming risk factors

Prevention of recurrent stone formation will only be possible with careful metabolic evaluation and appropriate management. In this present prospective study, a total of 95 patients with calcium oxalate (CaOx) stone disease were evaluated with respect to the effects of a calcium channel blocking agent (verapamil) therapy on stone-forming risk factors. A total of 95 patients with CaOx urolithiasis were well evaluated for the possible specific effects of verapamil administration on stone-forming risk factors during long-term follow-up. All patients had calcium-containing stones with normal renal morphology and function without any urinary tract infection. The follow-up period ranged from 12 to 36.6 months, with a mean value of 24.4 months. The age of the patients (54 male and 41 female; M/F: 1.31) ranged from 20 to 46 years (mean 34.3 years). On metabolic evaluation all patients had some kind of risk factors and patients were independently randomized into two groups, namely group 1 (n = 49): patients receiving calcium entry blocker, verapamil hydrochloride (isoptin 240 mg KKH tablets, oral t.i.d.); group 2 (n = 46): patients receiving no specific therapy (control patients) that were matched for sex and age. Follow-up results (at least 1 year) with respect to the changes in urinary stone-forming risk factors were recorded in both groups. During long-term follow-up patients undergoing no specific therapy did not show a significant change with respect to the urinary levels of stone-forming risk factors when compared with the others receiving verapamil on a regular basis. In the light of our results as well as the literature data, we believe that the pathophysiological mechanisms underlying the effect of verapamil on stone formation (as a result of enhanced crystal deposition) and on the excretion of the urinary stone-forming risk factors have to be well evaluated in further experimental as well as clinical studies. Although the exact mechanism of action is not clear; we may claim that the limitation of internal calcium shift by these agents may also well effect the tubular process related to oxalate handling which ultimately limits its excretion in urine.