This result is in agreement with Fuselier et al., who observed a small, but significant, decrease in urinary calcium excretion during treatment periods. Ali Tekin et al. evaluated, in an open clinical trial, the effects of oral potassium citrate therapy (22 months) in children with calcium stones and hypoc- itraturia; these Authors confirmed that potassium citrate reduces the recurrence of renal stones and seems to be a safe treatment. These Authors too, found a decrease in urinary calcium excretion although it remained within the normal range in most cases, so they concluded that potassium citrate seems to influence, to a low degree, calcium excretion. Moreover, in our paper, basal values of citraturia were lower than follow up values. However, when patients were sub- dived according to urinary citrate excretion, those with the lowest basal citraturia (citraturia lower than 320 mg/24 hours) behaved differently. In fact after a rise in the first year, urinary citrate excretion returned to values similar to or lower than basal value. Also Fuselier et al. observed that in 21% of patients treated with potassium citrate, urinary citrate excretion did not rise. The Authors stated the need for a careful follow-up of the patients treated with potassium citrate in order to identify patients requiring a more aggressive medical therapy and to properly modify the dose of alkali salts. Oxalate, uric acid and creatinine excretion as well as urine volume do not change during the follow up of patients treated with potassium citrate. Moreover potassium citrate does not usually induce an increase in the relative supersaturation ratio of brushite, as it reduces urinary calcium excretion, although an excessive amount of potassium citrate may increase the relative supersaturation ratio of brushite. Furthermore, in patients with distal renal tubular acidosis, potassium citrate treatment appears to improve calcium balance. 1 Internet Online Drugstore cialis professional
In fact it increases intestinal calcium absorption by means of a 1,25(OH)2D3 independent mechanism and reduces urinary calcium excretion. According to some authors, the decreased calcium excretion can be explained by an increased calcium reabsorption in the distal tubule induced by metabolic alkalosis as well as by the increased luminal pH. The chronic treatment with potassium citrate and other alkaline salts may result in a positive calcium balance. In fact a small but significant increase in bone mineral density in stone forming females has been shown. Also Sebastian et al., after treating a group of healthy postmenopausal women with potassium bicarbonate, observed an improved calcium balance through an interaction of bone remodelling phases. Several studies in vitro showed that citrate inhibits struvite formation. In fact it causes the chelation of magnesium, the disruption of the hydrogen and ionic binding of this mineral and the coating of the surface of struvite crystal. In conclusion alkaline citrate seems to be a rational approach to the treatment of nephrolithiasis in patients with or without hypocitraturia, as it reduces some risk factors involved in stone recurrence. Moreover this form of therapy presents a small number of side effects, mainly gastro-intestinal symptoms (e.g. diarrhea and nausea) and in very few cases hyperkaliemia. About the safety of potassium citrate supplementation there is a general agreement in literature; however Coe et al. report some experimental papers showing that citrate increases intestinal absorption of some metals such as aluminum and lead. These Authors suggest renal function in patients with renal failure should be carefully evaluated to avoid an increased intestinal absorption of aluminum, particularly if they are treated with aluminum antacids. The same precautions may be of some use also in patients with renal stones.