Potassium-magnesium citrate is an effective prophylaxis against recurrent calcium oxalate nephrolithiasis.

PURPOSE: We examined the efficacy of potassium-magnesium citrate in preventing recurrent calcium oxalate kidney calculi. MATERIALS AND METHODS: We conducted a prospective double-blind study of 64 patients who were randomly assigned to receive placebo or potassium-magnesium citrate (42 mEq. potassium, 21 mEq. magnesium, and 63 mEq. citrate) daily for up to 3 years. RESULTS. New calculi formed in 63.6% of subjects receiving placebo and in 12.9% of subjects receiving potassium-magnesium citrate. When compared with placebo, the relative risk of treatment failure for potassium-magnesium citrate was 0.16 (95% confidence interval 0.05 to 0.46). Potassium-magnesium citrate had a statistically significant effect (relative risk 0.10, 95% confidence interval 0.03 to 0.36) even after adjustment for possible confounders, including age, pretreatment calculous event rate and urinary biochemical abnormalities. CONCLUSIONS: Potassium-magnesium citrate effectively prevents recurrent calcium oxalate stones, and this treatment given for up to 3 years reduces risk of recurrence by 85%.

Comparison of endometrial growth produced by unopposed conjugated estrogens or by micronized estradiol in postmenopausal women.

OBJECTIVE: When unopposed estrogen replacement treatment is used, what is the pattern of endometrial growth? Does endometrial growth differ for various dosages and formulations? STUDY DESIGN: A total of 87 postmenopausal women, median age 57 years (mean 56.7 +/- 5.6 years, range 45 to 69 years), were studied in a prospective, randomized, open clinical trial lasting 24 weeks. The treatment arms consisted of micronized estradiol, 0.5 or 1.0 mg (Estrace, Bristol-Myers Squibb, Princeton, N.J.), and conjugated estrogens, 0.625 mg (Premarin, Wyeth-Ayerst, Philadelphia). Endometrial thickness was evaluated by vaginal probe ultrasonography at outset and after 6, 12, and 24 weeks of treatment. RESULTS: Endometrial growth was progressive over time; more than half the total 24-week growth occurred in the first 6 weeks. The mean weekly rate (+/-SD) of endometrial growth was similar for micronized estradiol, 1.0 mg, and conjugated estrogens, 0.625 mg (0.19 +/- 0.15 mm for micronized estradiol, 1.0 mg, and 0.19 +/- 0.14 mm for conjugated estrogens, 0.625 mg). These rates differed to a statistically significant degree (p < 0.05) from the growth rate produced by micronized estradiol, 0.5 mg (0.08 +/- 0.16 mm). Both unscheduled and scheduled uterine bleeding was less likely among women using micronized estradiol, 0.5 mg, than among women using micronized estradiol, 1.0 mg, or conjugated estrogens, 0.625 mg. CONCLUSIONS: In a 24-week trial the therapeutically equivalent estrogen doses produced the same mean increment in endometrial thickness, but half-strength estradiol produced half as much endometrial growth.

Cyclic hormone replacement therapy using quarterly progestin.

OBJECTIVES: To determine whether cyclic progestin, when part of postmenopausal hormone replacement therapy, can be used quarterly instead of monthly without increasing the risk of endometrial hyperplasia. In addition, we determined whether this hormone replacement therapy regimen produces an acceptable menstrual pattern. METHODS: The subjects were 214 postmenopausal women, mean (+/- standard deviation) age 56.2 +/- 5.4 years, who had regularly used hormone replacement therapy (consisting of Premarin 0.625 mg/day with monthly cyclic medroxyprogesterone, 5 or 10 mg) for a mean of 5.4 +/- 4.5 years (minimum 1 year). The study intervention consisted of changing the subjects' treatment from the usual monthly progestin to four 3-month (ie, quarterly) cycles of medroxyprogesterone, 10 mg/day for 14 days. Endometrial histology was evaluated by doing endometrial biopsies at study outset and after 1 year. Scheduled and unscheduled vaginal bleeding was reported in daily diaries. RESULTS: Endometrial hyperplasia was found in 1.5% of 199 women completing follow-up, a rate similar to the 0.9% prevalence found at baseline. Compared with monthly medroxyprogesterone, quarterly medroxyprogesterone resulted in longer menses (7.7 +/- 2.9 versus 5.4 +/- 2.0 days) and more reports of heavy menses (31.1 versus 8.0%) and unscheduled bleeding (15.5 versus 6.8%). Despite these problems, women preferred the quarterly regimen by nearly four to one. CONCLUSIONS: In a 1-year trial, quarterly medroxyprogesterone appeared as safe as monthly medroxyprogesterone and was preferred by most women. This schedule may be useful for women seeking relief from monthly use of progestin and monthly menses.