Effects of Potassium Citrate in Urine of Children With Elevated Calcium in Urine and Kidney Stones
Information source: Children's Mercy Hospital Kansas City
Information obtained from ClinicalTrials.gov on June 20, 2008
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Kidney Calculi
Intervention: Potassium Citrate (Drug); Acetazolamide (Drug); Diet low in oxalate and purines (Behavioral)
Phase: N/A
Status: Completed
Sponsored by: Children's Mercy Hospital Kansas City Official(s) and/or principal investigator(s):
Ari Auron, MD, Principal Investigator, Affiliation: The Children's Mercy Hospital
Summary
High amounts of calcium in the urine (hypercalciuria) can cause development of kidney stones
in children. Treatment for these children includes plenty of fluids, a low-salt diet and
medications such as potassium citrate. A major advantage of potassium citrate, as compared to
hydrochlorothiazide, is its lack of side effects. One problem the researchers and others
have observed is that some children continue to form kidney stones despite correction of
hypercalciuria with potassium citrate. One possible explanation is that in some individuals
potassium citrate therapy results in an excessive elevation of urine pH, a situation that may
predispose to calcium phosphate stone formation. In this study, the researchers will study
the effects of potassium citrate on urine chemistries and acid-base balance in three groups
of children aged 5-17 years:
- children who are hypercalciuric stone formers;
- healthy children without a history of hypercalciuria or kidney stones.
Particular attention will be paid to try to identify those who develop a very high urine pH
(>8) and the factors leading to this metabolic reaction.
The researchers will try to learn whether it is the child’s characteristics, the disease
manifestations, the dose of the drug, or a combination of the above which may be the cause of
the development of very alkaline urine. Based on the results, the researchers hope to be able
to better “tailor” the individual treatment for each child with kidney stones.
Clinical Details
Official title: Urinary Chemistry and Acid-Base Effects of Potassium Citrate in Children With Idiopathic Hypercalciuria and Urolithiasis
Study design: Diagnostic, Non-Randomized, Open Label, Dose Comparison, Single Group Assignment, Efficacy Study
Primary outcome: Changes in urine pH, citrate, calcium and bicarbonate after treatment with increasing doses of potassium citrate
Detailed description:
Hypercalciuria is a common clinical pediatric problem that in some children is associated
with renal stones. Most renal stones (80%) are formed by calcium oxalate, calcium phosphate
phases (apatite), and brushite (calcium monohydrogen phosphate). Hypercalciuria can be
either primary (accounts for the vast majority of children with calcium stones) or secondary.
Treatment for children with calcium stones involves non-pharmacological and pharmacological
interventions. Non-pharmacological interventions include high fluid intake, low sodium, and
potassium enhanced diet, with RDA calcium and protein. Historically, the specific treatment
for hypercalciuric stone formers has included thiazides, which reduce calciuria, lower the
urinary saturation of calcium oxalate and phosphate, and restore normal intestinal calcium
absorption. However thiazides induce hypokalemia and hypocitraturia, and the latter
attenuates the beneficial effects of the drug on stone formation. Currently, the drug of
choice replacing thiazides in treating idiopathic hypercalciuria is potassium citrate.
Potassium citrate is readily absorbed from the gastrointestinal tract, and after being
excreted in the urine, it inhibits the crystallization of stone forming calcium salts by
binding the calcium ion, thus decreasing its urinary saturation and inhibiting the nucleation
and crystal growth of calcium oxalate; therefore, potassium citrate is an effective stone
inhibitor agent. A major advantage of potassium citrate is its lack of side effects. One of
the problems seen in clinical practice is that some children with primary hypercalciuria,
even after the calciuria is treated successfully with potassium citrate, continue to develop
stones. It has been suggested that an elevation in urine pH, seen in some patients treated
with potassium citrate, may result in an alkaline urinary milieu which promotes calcium
phosphate stone formation. In this study, the researchers plan to investigate the effects of
potassium citrate on urine chemistries and acid-base balance in children who are
hypercalciuric stone formers. The researchers will try to identify whether the beneficial
effects of potassium citrate supplementation on lowering urine calcium and increasing citrate
might be offset by too high urine pH (>8) which could promote the formation of calcium
phosphate stones. Three groups of subjects aged 5-17 years will be studied: group 1 - idiopathic hypercalciuric stone formers; group 2 - idiopathic hypercalciuric non-stone formers; and group 3 - normocalciuric subjects. Three visits will be scheduled for each
participant, and the subjects will receive two doses of potassium citrate. Urine chemistries
and acid-base parameters will be measured. The researchers will try to learn whether it is
the child’s characteristics, the disease manifestations, the dose of the drug, or a
combination of the above which may be the cause of the development of very alkaline urine.
Based on the study results, the researchers hope to be able to better “tailor” the individual
treatment for each child with kidney stones due to idiopathic hypercalciuria.
Eligibility
Minimum age: 5 Years.
Maximum age: 17 Years.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- Children aged 5-17 years with idiopathic hypercalciuria who have history of kidney
stones.
- Healthy children aged 5-17 years without a history of hypercalciuria or kidney
stones.
Exclusion Criteria:
- Children with urolithiasis secondary to metabolic disorders unrelated to
hypercalciuria (e. g. oxaluria, hypocitraturia, cystinuria), or due to secondary causes
of calciuria (hypercalcemia, hyperparathyroidism, corticosteroids, furosemide).
- Children with renal insufficiency, active urinary tract infection, hyperkalemia,
gastrointestinal diseases, heart failure.
- Children who receive angiotensin-converting enzyme inhibitors, anticholinergic
medications or digitalis.
- Children who cannot safely stop receiving the prohibited concomitant medications due
to other underlying medical conditions
Locations and Contacts
The Children's Mercy Hospital, Kansas City, Missouri 64108, United States
Additional Information
Related publications: Tapaneya-Olarn W, Khositseth S, Tapaneya-Olarn C, Teerakarnjana N, Chaichanajarernkul U, Stitchantrakul W, Petchthong T. The optimal dose of potassium citrate in the treatment of children with distal renal tubular acidosis. J Med Assoc Thai. 2002 Nov;85 Suppl 4:S1143-9.
Starting date: July 2005
Ending date: May 2007
Last updated: June 14, 2007
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