Editing Stones: Evaluation and Medical Management (section)

===Uric acid stones===
*'''<span style="color:#ff0000">First-line therapy for patients with uric acid stones is alkalinization of the urine with potassium citrate to raise urinary pH to an optimal level so that uric acid remains in a dissolved state.</span>'''
**'''<span style="color:#ff0000">Allopurinol should not be routinely offered as first-line therapy to patients with uric acid stones</span>'''
***'''Most patients with uric acid stones have low urinary pH rather than hyperuricosuria as the predominant risk factor'''
***'''<span style="color:#ff0000">Goal is to increase the urinary pH > 5.5 (AUA targets 6.0 and CUA targets 6.5), through an alkalinizing agent such as potassium citrate'''
**** With adequate alkali therapy, patient's can raise the urine pH to an optimal level so that uric acid remains in a dissolved state.
***** '''<span style="color:#ff0000">Attempts at alkalinizing the urine to a pH > 7.0 should be avoided. At a higher pH, there is a danger of increasing the risk for calcium phosphate stone formation.'''
***Patients may initially present with low/normal 24-hour urinary uric acid levels because the uric acid will precipitate out of solution in the acid urinary environment. Once the urine has been alkalized, all of the uric acid will come back into solution, causing a significant increase in the measured urinary uric acid.
*'''<span style="color:#ff0000">Allopurinol may be considered as an adjunct when alkalinization is not successful or for patients who continue to form uric acid stones despite adequate alkalinization of the urine.</span>'''
**'''Allopurinol (300 mg/day) may be used'''
*** MOA: blocks the ability of xanthine oxidase to convert xanthine to uric acid, resulting in decreased production of uric acid
**** The resultant decrease in serum uric acid will ultimately lead to a decrease in urinary uric acid as well.
* '''Acetazolamide is effective in increasing the urinary pH in patients with uric acid and cystine stone formation who are already taking potassium citrate.'''
** Acetazolamide, a carbonic anhydrase inhibitor, leads to an increase in urinary bicarbonate and increased H+ reabsorption.
** Up to 50% of patients may discontinue acetazolamide due to adverse effects.