Chapter Eight: Uric Acid Stones

Uric acid stones, to me, means not just pure uric acid stones but any uric acid in stones. If this seems fey, let me explain. Uric acid is a peculiar kind of crystal. Low urine pH causes them and treatment that raise urine pH prevent them altogether. Whether they form combined with calcium stones or pure, treatment is the same.

Why then scruple over percentages? If I find uric acid in any stone, I look at urine pH with a yellow eye. Should it be low I treat it surely and on the moment so at least that crystal be banished forever.

The Profligate Punished by Neglect, Edward Penny 1774 catches the common motif of diet excess, obesity, diabetes, and gout – the joint manifestations of uric acid crystals. Note the abdominal fat denoted by his overly tight vest. All of these states can lower urine pH and lead to uric acid stones.

This article has a pragmatic leaning and eschews excessive scientific details. I have written a more mechanistic article that explores how the low urine pH might arise and cause uric acid stones. Read this one first unless you are already reasonably expert.

Who Are Uric Acid Stone Formers

Stone Analysis

Given my prior reasoning, I call patients who have any uric acid in their stones uric acid stone formers but reserve the right to use compound names when needed. If all stones are only uric acid, I call such patients pure uric acid stone formers. Those whose stones contain uric acid and other crystals I call mixed uric acid /x stone formers: mixed uric acid calcium oxalate, mixed uric acid calcium phosphate stone formers, as examples.

These niceties of naming have the practical value of calling to mind the perpetual need for dual or multiple treatments – for uric acid but also for whatever crystals might be present.

Radiographic Evaluation

Commonly uric acid stones show poorly on routine flat plate x rays having only carbon, nitrogen, oxygen and no heavier atoms such as calcium. On CT scans they do not look different from calcium stones but radiographic density can be measured and tends to be lower. As this article points out, machines differ in their results and evaluation may therefore be less than perfect. Dual energy scanners are more precise, but also prone to many potential artefacts. Multiple reports, by contrast, indicate that CT measurements of radiographic density can reliably distinguish uric acid stones from calcium stones.

A reasonable present view is that lower radiographic density is an excellent clue to uric acid in stones, but far from definitive as stone analysis is. I hesitate to classify a patient on scanning evidence alone.

Signs and Symptoms of Uric Acid Stones

Pigmented Stones and Crystals

Being stones, uric acid stones cause the usual problems of pain, obstruction, bleeding and infection. But they have some special features. The most obvious is stone color – red to orange because the crystals take up a variety of pigments mostly derived from hemoglobin breakdown. Recently scientists have determined the structure of one of these – urorosein.  Sometimes, coarse or fine orange or red gravel passes, made up of uric acid crystals.

Rapid Crystallization, and Stone Growth

Because the crystals form not as a complex lattice like calcium with oxalate or with phosphate but simply as uric acid crystallizing with itself, the process can be swift to begin and require very little supersaturation. Said more technically the energy required to create the crystal is relatively low. This means the upper limit of metastability – the supersaturation needed to initiate crystal formation is not far from solubility, so values above 1 even if below 2, could suffice. Practically it means that bursts of supersaturation during the day can bring on showers of gravel and growth of stones.

Also, urine contains a lot of uric acid. Common daily losses of oxalate approximate perhaps 25 – 50 mg, compared to 600 – 1,000 mg of uric acid. The sheer amounts available when coupled to the rapid and facile crystal formation and growth allow stones to enlarge rapidly and achieve very large sizes, enough to fill the renal pelvis and calyces – so called staghorn stones.

Acute Uric Acid Nephropathy

Very uncommonly, sudden lowering of urine pH coupled with low urine volume can cause crystallizations in the terminal collecting ducts with acute kidney failure. This was once not uncommon during treatment of malignancies, but modern attention to uric acid surges from tumor killing has made it rare indeed. Today, one does not expect to see it apart from unusual situations

Uric Acid Supersaturation

I made the figures for this section anew but from a lovely data file constructed some years ago by Joan Parks, who was my scientific colleague from 1976 until her retirement about 8 years ago. Her legacy of curated data files sustains a lot of my public writing, now, and she deserves a place in it. 

Effects of Urine pH

Uric acid crystals form like all crystals because of supersaturation. In this instance, that supersaturation varies remarkably with urine pH.

In the figure, supersaturation ranges from 0.01 to 10 fold. The dashed line at 1 represents equilibrium, or saturation, the level where crystals neither form nor dissolve. The horizontal axis shows urine pH. The dashed lines at 5.5 – acid urine and 6 neither acid nor alkaline urine are for visual reference.

The tiny points each are one 24 hour urine from patients and normal people. Like an ancient Persian scimitar, points curve downward from 8 to 0.03 as pH rises from 4.5 to 7.5.

Effects of Urine Volume

Urine volume matters. Low volumes (red) 0.5 to 1 liter/day give higher supersaturation than 1 to 1.5 liters/day (green), and 1.5 to 2 and above 2 liters/day (blue and black) lower supersaturation progressively.

But pH trumps volume. At pH 5.5, the whose distance from red to black varies supersaturation between about 2 and 5 fold (use the lines for averages) whereas raising pH from 5.5 to 6 brings almost all the points down below 1. Below 5.5 virtually no points are below 1 at even above 2 liters of urine volume daily.

Effects of Uric Acid Excretion

In speaking about excretion of uric acid we need to insert a note about the molecular species involved.

Form of Uric Acid in Urine

Uric acid is a weak acid, which means it can take up or donate a proton to water. When it has its proton, that proton neutralizes much of its charge, so water molecules cannot themselves form charge bonds with it to keep it in solution. This means that the molecule becomes very poorly soluble and tends to crystallize.

When it loses its proton into solution, it has a charged site for water to relate to and also requires a counterion, which in urine will be sodium, potassium, and ammonium ion. These ‘salts’ of urate – the name for uric acid when it has given up its proton and is a charged ion – can themselves form crystals just like calcium and oxalate form a salt – calcium oxalate – that can crystallize. But all three salts have much higher solubility than uric acid itself.

Effect of Uric Acid Excretion on Supersaturation

When we measure and report urine uric acid excretion we show the sum of all salts and the acid in one number. Obviously this total should affect supersaturation, but the effect is relatively small because so much depends on pH that sets the percentage of uric acid per se – the fraction that has its proton and is therefore poorly soluble.

Here, red, green, blue and black stand for below 500, 500 to 750, 750 to 1,000, and over 1,000 mg/d of urine uric acid excretion respectively. As for urine volume, the total amount of uric acid matters; a fivefold increase from below 500 mg to over 1,000 mg/day raises supersaturation at pH 5.5 from about 1.2 to about 3 fold.

Urine pH of Stone Formers

One presumes that urine pH of uric acid stone formers must lie below that of other kinds of stone formers, and numerous reviews and case descriptions have proven this true.

My own collected data make the point as well as any.

The dot distribution just below shows individual 24 hour urine pH measurements for calcium oxalate (blue), calcium phosphate (green) and uric acid (red) stone formers. Here I include among uric acid stone formers those with both pure and mixed stones.

Calcium oxalate stone former pH ranges widely with an average at about 5.8 pH units. Calcium phosphate stone formers average a lot higher – around 6.4.

Uric acid stone formers lie in an acid range. Their average is about 5.3 – 5.4 and only a tiny scattering of points range above 6. So uric acid stone formers produce a very acid urine compared to other stone formers, and the pH is exactly in the range to produce supersaturation that can drive formation of uric acid stones and hold them steady or cause them to grow.

To see this, just look back on the graphs showing supersaturation vs. urine pH. Below 5.5 values almost all lie above 1 – solubility – meaning that crystals can form and grow.

UA Fraction in Stones

The General Pattern

I have said that any uric acid in stones means pH should be raised because at least that portion of the stone burden might dissolve or at leasts not grow.

The figure below shows urine pH associated not with the kind of patient – calcium oxalate, calcium phosphate or uric acid stone former, but by the fraction of a given stone made up of uric acid.

Blue means no uric acid at all. Red means 100% of the stone is uric acid, and pink and green lesser amounts. With a scattered few points as exceptions, stones made of mainly uric acid go with urine pH values mostly below 5.5.

The graph makes a point we often speak of but rarely show. Oxalic acid has a very low pKa – is a strong weak acid. So it has charges available for binding to calcium that very hardly at all with urine pH all the way down to 4.5, about the lowest value human kidneys attain. So these stone crystals are indifferent to pH.

Paucity of Mixed Stones

I makes another point, too, one that a patient emphasized in a comment to this article and that I failed to mention in the original version. Of all stones that contain any uric acid, at least in my collection of data, most are mainly composed of uric acid. See where the red – pure uric acid – stones make up the largest mass in the figure just above?

This is not to say that patients are uncommon who make both calcium and uric acid stones – mixed stone formers. The graph shows the stones themselves. People who make both kinds of stones need treatment with alkali so they will stop making uric acid crystals. They also may need treatment against their calcium stones. Stones that contain both uric acid and calcium – usually calcium oxalate – mean the patients may need treatment against both their uric acid stone formation – that would be alkali, and for their calcium stone forming.

So in the final analysis, whether the stones are mixed, or patients form both uric acid and calcium stones the answer is the same: Treat against both crystals.

Who Produce Uric Acid Stones?

Low pH Without Intestinal Disease

Genetic Factors

In identical twin studies, urine pH had only a 60% concordance compared to over 90% for calcium excretion. In a larger study urine pH seems as heritable as urine calcium excretion. Of interest, such dietary traits as sugar, calcium, and protein consumption that could influence stone formation also had significant heritability.

Systemic Disorders

Historically, uric acid stones have been linked to gout. A recent but brief review repeats that fact. Likewise, another review.

Given low urine pH drives uric acid crystallization, one has to ask whether some kinds of patients might be expected to produce acid urines. In answer, those most common are obese, older, diabetic, hypertensive, and prone to modest reduction of kidney function. Obesity itself, without necessarily overt diabetes correlates with lower urine pH in a progressive manner – as obesity increases urine pH falls

Resistance to the actions of insulin – so called insulin resistance – is often invoked as a general paradigm to encompass the general class of abnormalities that lower urine pH. Metabolic syndrome, a mix of insulin resistance with lipid and vascular abnormalities is linked to kidney stones. But not to uric acid stones per se. Attempts to link uric acid stones to gut bacteria – use of the genetically defined biome -failed in a tiny study to disclose any species unique to uric acid stones.

Kidney Physiology

At least one specific abnormality that produces the low pH is an inadequate production of ammonia with which kidneys can remove acid. I plan another article on uric acid stone formation that will review the underlying disease mechanisms, and do not wish to burden this text with more detail. The linked articles from the group at UT Southwestern Medical School give access to the best current work on the subject. Essentially uric acid stone formers respond to acid load with less ammonia than normal people. Insulin resistance probably produces the renal tubule abnormality.

The issue is complex, as illustrated by a recent publication that found no evidence for low urine ammonia in uric acid stone formers. But the conditions of that study – mere measurements made in uric acid stone formers with comparisons to normal ranges hardly have any power to test the ammonia hypothesis.

In an elegant analysis of a single patient, Kamel and his colleagues point out two matters I use in my own work. Urine ammonia needs to be viewed in relation to urine sulfate – the net acid load. Likewise, the low urine ammonia of their case was accompanied by a high urine citrate – this occurs when proximal tubule cells consider themselves in an alkaline state that would cause a fall in ammonia production

I have allowed myself a bit more about the urine pH than perhaps is ideal, and will end here. Either I will write another article on this subject or expand this one with my own data on ammonia and citrate.

Intestinal Causes

Intestinal Diseases

Any organic cause of diarrhea can lower urine pH because the fluids contain appreciable bicarbonate, the main blood buffer. In turn kidneys increase acid excretion in compensation. This requires both an increase of ammonia excretion and lowering of urine pH. Common situations include small bowel resection for such conditions as Crohn disease and partial or complete loss of colon. The latter, ileostomy, can cause marked alkali loss with acid urine and uric acid stones.

Chronic intestinal fluid losses also deplete body sodium and potassium. The 24 hour urine is very valuable for assessing both as excretion rates fall with such losses. Repletion with a mixture of sodium and potassium alkali is often valuable.

Bariatric Surgery

Howsoever valuable, these can result in both enteric hyperoxaluria and chronic alkali loss so calcium oxalate and uric acid stones do occur. The former are more common. This recent and excellent review details new stone frequencies but stone analyses are not widely reported so I cannot state the balance between calcium oxalate and uric acid crystals. Treatment with potassium alkali is recommended to increase citrate and pH.

Overuse of Laxatives

By increasing Gi fluid and alkali losses one might think these drugs would cause uric acid stones. In fact, a recent review of reported cases – not many! – suggests that mainly low urine volumes from fluid loss causes calcium stones. Not uric acid, in fact, but ammonium urate stones have been documented. I presume they represent induction of ammonia production by the potassium depletion from the diarrhea. As ammonia increases urine pH can rise despite loss of alkali and the higher pH would favor the ammonium acid urate salt.

What Happens With Treatment

Changes in Urine pH

In principle, potassium alkali in the proper dose will raise urine pH and abolish uric acid formation. The reality of practice has a bit less perfection.

These are data from my own work.

The original pretreatment urine pH values are at the top of the figure, for reference, in red. Below them, in pink squares the treatment data show a large shift toward high urine pH so that a majority of values lie above the pretreatment ones. But some patients did not take their medications, and in some I miscalculated the dose needed.

Even with this natural variation in physician intent and patient willingness, the shift of pH with treatment was drastic in my own practice.

Given the powerful dominance of pH over supersaturation, I decided to not add a figure showing that supersaturation fell – it would be redundant.

Treatment Complexities


Although potassium alkali – potassium citrate or potassium bicarbonate preparations are an obvious and widely used treatment, the kind of patients involved – often older, diabetic – may not tolerate large amounts of extra potassium without increasing serum potassium. Especially, common and effective blood pressure medications such as angiotensin converting enzyme inhibitors or receptor blockers can worsen the risk. Typically most clinicians are aware of the problem and proceed based on serum potassium level and whether kidney function is normal or not. Sometimes I use a low dose of thiazide diuretic along with potassium citrate – the diuretic to foster renal potassium loss. This can enable patients to get more alkali without risk of raising serum potassium.


In the intestinal diseases, sodium depletion may be great enough one wants to use sodium alkali. I prefer inexpensive sodium bicarbonate tablets bought over the counter, being cheap and easy to use. Two provide about 13 mEq of base.


I almost always begin with 40 mEq daily and repeat the 24 hour urine measurements. Spot urine pH testing with pH paper never impresses me as very useful because results scatter and, after all, what most matters is average supersaturation over the day. These crystals can form and dissolve rather rapidly, and one hopes to achieve 24 hour average SS below 1. Overnight is clearly a high risk because of lower urine volumes so a nighttime dose of alkali before bed seems reasonable. If I need to I increase dosing in 20 mEq/day increments.

Effect on Uric Acid Stones

Uric acid in stones has a different meaning than we attach to calcium oxalate or calcium phosphate, or even cystine. This crystal can be prevented by raising urine pH within the common physiological range between 4.5 and 6. This means that simple alkali treatment should and will prevent such crystals in stones. Likewise, lowering supersaturation below 1 must eventually reduce kidney stone mass. Put another way, not guile or special knowledge but simply persistence with alkali use must inevitably stop uric acid crystallization.

Even so, data are hard to come by. This small report says that 91% of 24 uric acid stone formers treated with potassium citrate had no recurrence after a mean of 31 months.

No Formal Trials

A look on PubMed found no prospective uric acid stone prevention trials.

(For the purists, this was my search: ((“prevention and control”[Subheading] OR (“prevention”[All Fields] AND “control”[All Fields]) OR “prevention and control”[All Fields] OR “prevention”[All Fields]) AND (“uric acid”[MeSH Terms] OR (“uric”[All Fields] AND “acid”[All Fields]) OR “uric acid”[All Fields]) AND (“calculi”[MeSH Terms] OR “calculi”[All Fields] OR “stones”[All Fields])) AND Clinical Trial[ptyp])

I am not surprised. Given all we know can we assign such patients to a control group that does not receive alkali? Given the ease of use should one even try to do so?

I say not.


223 Responses to “Chapter Eight: Uric Acid Stones”

  1. John

    Hi Dr Coe,
    When you say 40 mEq of potassium citrate is it the same for the extended release tablet and is it 40 mEq in one dose or throughout the day?

    • Fredric L Coe, MD

      Hi John, the usual form is 10 mEq tablets, and I favor 2 twice a day to spread out the effect. But you need 24 hour urine testing to be sure the 24 hour average is at least pH 6. Regards, Fred Coe

  2. Tony

    Hello Dr. Coe,
    Thank you for sharing your knowledge about this painful affliction. I truly appreciate your work. I am a uric acid stone former.
    Would taking apple cider vinegar tablets help in any way to prevent stone formation?
    Thank you again,

    • Fredric L Coe, MD

      Hi Tony, No. As the article points out proper dosing with medicinal alkali is curative so why play around? Low urine pH causes uric acid stones, alkali to raise urine pH prevents them and can even cause some to dissolve. Just get real alkali, raise urine pH above 6 on a 24 hour average, and you are done with them. Vinegar is nice in salads, I guess, but hardly a match for a sure cure. Regards, fred

  3. Elena

    Hello Doctor,
    So, I am a 23 year old woman who just had a Lithotripsy of a 6mm stone. My urologist however found I had 8 smaller ones still between my two kidneys. I had been experiencing/presumably passing stones since I was about 18 and experience what I now can identify as kidney pain nearly every day. I have a primarily very healthy plant based diet and don’t do fast food or tea or soda or dairy. I am also really active, despite having discomfort. Now, I did a 24 hour urine sample and my results shocked my urologist. My oxalate levels, which was thought to be my problem, were normal, however my uric acid level was at 1,099, my calcium at 324, and my magnesium at 175. So, he referred me to a kidney specialist in my area. This all being said, it’s been a month and I haven’t heard from the specialist yet and am just baffled as to how my uric acid is so high. I strained my stone I ended up having to pass in the hospital and it was a darker color, not the red/orange you described. This is all just so puzzling to me. My dad and his dad had chronic kidney stones, however my dad’s are potassium based. Any advice here?

  4. Dave

    Hi Dr. Coe,

    I’m a 56 year old man who has stage 3 kidney disease, controlled diabetes, and normal blood pressure. After going to the emergency room last year in June with an incredible amount of pain. I had a ureteroscopy to remove a 7mm kidney stone. It was my first
    Kidney stone surgery. For whatever reason, no stone analysis was done at the time. About 3 weeks later, I peed out a bunch of small stones which were caught in a strainer. After lab analysis, the stones were determined to be made up of 100% uric acid. Blood work and a 24 hour urine analysis soon after revealed that I had a high parathyroid level, normal calcium, a urine PH of 5.4, a high urine super saturation of both uric acid and CaOx, and 1 liter of collected urine. I refused to follow my doctors recommendation at the time to take Potassium Citrate because I thought things might improve on their own and wanted to avoid experiencing the unpleasant medication side effects. About 3 weeks ago, I had those same tests again with very close to the same results above. The urine PH this time was 5.36. I also had a ultrasound which revealed about 5 kidney stones, 4 under 3 mm and 1 that was 8mm. The doctor again wanted me to start taking the potassium citrate, Urocit-k. I decided to do that, but first wanted to try a change in diet to see if it would make a difference, and it did in a very short period of time. I stopped eating fast food, I had been eating it 2 to 3 times a week. I cut down on my meat consumption and stopped drinking so much seltzer water. After 4 days my urine PH, which I’ve been testing at least 3 times a day with PH meter, jumped from an average of 5.4 to 6.2. My questions are why do you think the diet may have made a difference and if the PH remains over 6, is it necessary that I take the potassium citrate? Thanks.

    • Fredric L Coe, MD

      Hi Dave, as in the article, pH is all there is to uric acid stones, so if you got to 6 on 24 hour testing you are done. But I am not sure if you are doing spot testing or 24 hour urine. Spot testing is not ideal as stones form in response to the integrated pH and one does have overnight etc. My advice – very confident – is to use 24 hour urine testing to be sure your diet has raised 24 hour urine pH to 6. I suspect it did not and you will need alkali. Regards, Fred Coe

      • Dave

        Thanks, Dr. Coe..
        Just one follow up.. I was prescribed and started taking potassium citrate, which unfortunately, I wasn’t able to tolerate, even at the lowest dose, 5 mEQ. When I take it, I get heart arrhythmias. Anything else I can do or try at his point or should I just resign myself to the possibility that I’ll have many more stone surgeries in the future? I bought a PH meter awhile ago and have been testing myself multiple times a day. My PH is still low, averaging about 5.4.
        With regards to my 8 mm non obstructive stone, do you think it should be removed as soon as possible? My urologist didn’t think it needed to be.

        • Fredric L Coe, MD

          Hi Dave, Raise the urine pH another way, then. There are many options including sodium bicarbonate and sodium citrate alkali. The non obstructive stone may be uric acid and might shrink as you raise urine pH. Regards, Fred Coe

  5. Steve F

    Thank you for the valuable info, Dr. Coe. I will follow your recommendations to the letter…take care!

  6. Steve F

    I am facing a PCNL treatment for a uric acid stone in my left kidney. My urologist does not believe it can pass and is recommending the PCNL treatment. Obviously, I don’t want it. Can sodium bicarbonate dissolve the stone? If so, how much is considered a safe, conservative amount to take. My urologist is dubious that either potassium citrate or bicarbonate would reduce the size of the stone. I have roughly a month and half before my next appointment. Thank you for any information!

    • Fredric L Coe, MD

      Hi Steve, It is a pity that uric acid stone got big enough to require a PERC. Your surgeon is probably right but I would push to try dissolving it. The stones are often built up of many smaller stones, so with a high urine pH – 6.5 – they sometimes come apart into smaller ones. There is no harm in trying, and the one month is not a deadline. Of course, stay on K citrate life long, so no more form. Regards, Fred Coe

      • Steve F

        Thank you for the response, Dr. Coe. If my urologists does not want to go to attempt to try either citrate or bicarbonate, is it safe for me to attempt to do it on my own? What is the usual amount of time it takes to break up a uric acid stone with either of these substances and how will I know if it is working (short of passing the stone)?

        • Fredric L Coe, MD

          Hi Steve, Not really. Perhaps the stone compromises drainage within the kidney, she/he would know and you would not. pieces may detach and cause obstruction – this needs an active physician. If you want to try alkali and your physician will not support that desire, I would suggest you ask her/him to help you get a second opinion. Alternatively, you are free to choose a second opinion. Do not venture off apart from physician recommendation – it is not safe. Regards, Fred Coe

  7. Daniel Mulugeta

    thank you very much for your response. I will get CT scan get the density of the stones. On sodium bicarbonate, can I only take it when urine pH is above 6? on urine pH when is the perfect time to measure it, as amount of water intake clearly affect urine solution? on stone density which one have a higher density between the crystals, is their a standard to followed for radiographer? and finally which medical pills are best from your huge experience to be considered? thank you very much. I am glad i found wise person to take advice from.

    • Fredric L Coe, MD

      Hi Daniel, Find out about the stone density before you do anything. If they are dense, like calcium stones, the advice about alkali would be wrong. The density is measured from a CT and the procedure is standard for all physicians to perform. Regards, Fred Coe

      • Dave

        Some good news, Dr. Coe. I started a trial of baking soda Friday evening, .5 tsp twice a day, morning and night. After 13 PH readings over the course of approximately 36 hours, my PH average is now 6.53. The PH average over the course of the past 7 readings is 6.72. Before taking the baking soda, the average was 5.4. No heart arrythmias as I was experiencing on the pottasium citrate, and so far, no effect on my blood pressure. I’m hoping the higher PH will desolve my current stones (one 8 mm) and prevent new stones from forming. The only thing I don’t like is the taste of the baking soda water solution. Yuck. I ordered some sodium bicarb pills online, 325 mg. Im planning to take 2 a day. I hope that’s the correct dose and in addition, that I can take the pills without having to disolve them in water first. I asked my Urologist about the sodium bicarb beofre taking it. He told me he doesn’t treat his patients with it and referred me to a nephrologist.

        • Fredric L Coe, MD

          Hi Dave, I am glad you are doing this. Two pills contain about 325 mg/pill x 2 = 650 mg/84 mg per mmeq sodium bicarbonate = 7.7 meq of base. So you need 2 pills 4 times a day to get any effect. Just swallow them. Fred

  8. Daniel Mulugeta

    I have a kidney stone and gout(pain in joints), am from country with no adequate resources to check for the type of crystal. I have seen different readings connecting uric acid with joint pain as well. can I be sure it is a uric acid stone from this? how could the potassium citrate affect some one with bad gastric problem?
    please give a good suggestion on how to eat, drink, and live my life and good home remedies to get potassium citrate from food.
    thank you.

    • Fredric L Coe

      Hi Daniel, If you have stones and gout the stones may well be uric acid. A CT scan can help as the radiographic density is a clue – in the article you are posting on. Potassium citrate can be unpleasant for people with gastric problems, but sodium bicarbonate is usually not a problem and it will dissolve uric acid stones. But you need at least the urine pH, which can be measured with inexpensive pH paper. It needs to be above 6. Of course you may not have gout or uric acid stones, and if your stones were calcium and you took sodium bicarbonate things might worsen. As for food, fruits and veggies are high in potassium and molecules like citrate that are metabolized to produce alkali. Put another way, there is a lot of uncertainty here, and therefore some concerns about how to proceed. My main issue is your stone. Can you get a CT and then a measure of its density. That one measure would make a great difference. Regards, Fred Coe

  9. Sharon W.

    Hi Dr. Coe, I am a mixed stone former (80% Uric Acid Dihydrate & 20% Calcium Oxalate Monohydrate). Based on everything I read on your site I have had the correct testing done by my doctors. I see both a urologist & a nephrologist. Just as you say on your site; through supersaturation I form stones quickly. Yes, I know I don’t drink enough! I’m also obese, have high blood pressure and uncontrolled diabetes. I have had four lithotripsies within the past 4 years. My doctor has prescribed 40 mEq of Potassium Citrate daily. I really, really want to take it as I know it would help; however, I have terrible side effects ; severe stomach pain, ulcers and GERD. I have also had many UTIs; 5 last year and 2 already this year. My urine ph is 5.5. Is there anything else I can take that would work the same way as Potassium Citrate? Is there some other form of it besides tablets? Thank you for any guidance you can provide.

    • Fredric L Coe

      Hi Sharon, Indeed you are the very archetype of uric acid stone former. You need the alkali. Lots of alternatives exist. There are liquid sodium/potassium citrate liquids, Crystal light lemonade has 20 mEq of potassium citrate per liter. You can take sodium bicarbonate pills, if needed, and your physician can prescribe a tiny dose of a diuretic if the sodium load raises your blood pressure – it usually will not being bicarbonate not sodium chloride. Your pharmacist can recommend alternatives forms of alkali with different flavors. But you need the alkali and a urine pH above 6 – cures the stones. Regards, Fred Coe

  10. John

    Good day,
    Was wondering if potassium citrate is something that can be taken for extended periods of time. I have done 1 month cycles. But was wondering if I can do 6 month cycles etc etc

    • Fredric L Coe

      Hi John, You need it every day forever. Uric acid crystallizes when urine becomes acidic, the potassium citrate prevents that. It is already in your blood – potassium and citrate – so what you take is a supplement. Use it daily. Lots of veggies and fruits provide potassium with citrate – like molecules so that can reduce the needed dose. Do not cycle it, use it. Regards, Fred Coe


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