How do you dissolve kidney stones?

CONDITIONS

Author: Ivo Dukic, Consultant Urological Surgeon specialising in kidney stone disease, BSc, MBChB, FRCS(Ed) Urol, PG Cert
Reviewed and amended: 13/03/2026, Version 2

Can Kidney Stones Be Dissolved?

Yes, certain kidney stones can be dissolved with a treatment called dissolution therapy. It is a safe and effective non-surgical option, but it only works for uric acid stones. Patients take oral medication that breaks down and dissolves the stones, which can eliminate the need for an operation.

Why Only Uric Acid Stones?

Dissolution therapy is a non-surgical treatment that specifically targets uric acid stones, which account for about 10% of all kidney stones [1]. This method is particularly useful because all uric acid stone formers are considered to be at high risk of recurrence [1].

Patients with metabolic risk factors are much more likely to form uric acid stones. Risk factors include:

obesity,
type 2 diabetes,
metabolic syndrome,
and insulin resistance are at significantly higher risk of forming uric acid stones [1].

This is because insulin resistance impairs the kidney's ability to excrete ammonium, a process known as ammoniagenesis, which results in persistently acidic urine [1][2]. Other causes of low urinary pH include high animal protein intake, chronic diarrhoea, and gout [1].

Elevated uric acid production may also result from dietary excess, endogenous overproduction, myeloproliferative disorders, or certain medications [1].

How It Works: Alkalinisation

The treatment works by making your urine less acidic, a process known as urine alkalinisation. You'll take medication that raises the pH of your urine. Because uric acid crystallises specifically in acidic conditions (typically at a urine pH below 5.5), this change in chemistry creates an environment where uric acid stones cannot stay solid, causing them to slowly dissolve over time [1].

How do you know if your stones can be dissolved?

Before starting treatment, your doctor needs to be reasonably sure that your stones are the uric acid type. Since you can't always get a piece of the stone to analyse without surgery, doctors use several diagnostic clues.

Urine and Blood Tests: A key indicator is the acidity of your urine. Uric acid stones form in acidic urine, so a low urine pH (often below 5.5) is a strong sign. Doctors may also check for elevated levels of uric acid in your blood (serum Uric Acid levels) [1].

Imaging: A non-contrast Computed Tomography (CT) scan is the most common imaging tool used. Uric acid stones are typically radiolucent, meaning they don't show up well on standard X-rays. On a CT scan, however, they are visible. Doctors can also measure their density in Hounsfield Units (HU). Uric acid stones tend to have a low density, typically in the range of 350–500 HU [3][4], which helps differentiate them from other, denser stone types like calcium oxalate. Research suggests that a stone larger than 4 mm with an HU measurement of 500 or less and a urine pH of 5.5 or less has a 90% chance of being a uric acid stone [5].

What to Expect from Treatment

Dissolution therapy is primarily administered through oral medication. The most common medications are alkalinising agents, with potassium citrate being the preferred first-line agent [6]. Potassium citrate is generally favoured over sodium-based alternatives (such as sodium bicarbonate) because a high sodium intake can increase urinary calcium excretion, potentially promoting the formation of calcium-containing stones [1]. Typical dosing regimens include potassium citrate 20 mEq three times daily or, where potassium citrate is not suitable, sodium bicarbonate 500 mg four times daily [4]. The landmark study by Pak et al. in 1986 first established the effectiveness of potassium citrate for the successful management of uric acid nephrolithiasis [6]. The goal is to raise your urine pH to a target level, which typically ranges from around 6.0 to 7.5.

In some cases, you may be asked to monitor your own urine pH at home using test strips and adjust your medication dose accordingly to stay within the target range. Treatment duration can vary significantly, from a few weeks to several months, with the average being around half a year in recent studies.

Alongside medication, your doctor will likely recommend increasing your daily fluid intake and may suggest a diet low in purines (found in red meat, organ meats, and some seafood). A medication such as allopurinol or febuxostat may also be prescribed. These drugs work by inhibiting the enzyme xanthine oxidase, reducing the amount of uric acid your body produces [7]. Allopurinol is not only used for long-term prevention; it can also be beneficial during active dissolution therapy itself, as decreasing the urate concentration in urine may enhance the effectiveness of alkalinisation [8]. Febuxostat has been shown to achieve urate-lowering targets in up to 86% of patients at doses of 80–120 mg daily, compared with allopurinol 300 mg daily [7].

What Are the Chances of Success?

The results from the comprehensive review are very encouraging. Overall, around 80% of patients saw either complete or partial dissolution of their uric acid stones [3].

When broken down further:

Around 60% of patients achieved complete dissolution, meaning their stones disappeared entirely on follow-up imaging. 20% of patients experienced partial dissolution (their stones got smaller but did not disappear). This high success rate means that a large majority of patients can avoid surgery.

However, the therapy isn't successful for everyone. Around 15–20% of patients ultimately require surgical intervention [1] to remove their stones. The therapy was generally well-tolerated; only about 10% of patients stopped the treatment due to side effects, non-compliance, or other reasons. The most common side effect was gastrointestinal disturbance.

The following link provides an overview of kidney stone surgical treatment.

In conclusion, for those with uric acid kidney stones, dissolution therapy stands out as a highly effective and safe first-line treatment that can eliminate stones without the need for an invasive procedure. If you have been diagnosed with kidney stones, it's worth discussing with your urologist whether this could be the right approach for you.

Mr Ivo Dukic is a top Consultant Urological Surgeon whose Birmingham-based practice is a leading UK centre for kidney stone removal. As one of the country's highest-volume stone surgeons, he is a primary choice for patients seeking unparalleled expertise and successful outcomes.

Mr Dukic has dedicated his practice to the surgical management of kidney stones, ensuring patients benefit from a depth of experience crucial for complex cases. His reputation is built on his mastery of advanced, minimally invasive techniques. He is a renowned specialist in Percutaneous Nephrolithotomy (PCNL), including ultra-modern mini-PCNL and ultra-mini PCNL procedures. These advanced treatments offer patients significantly faster recovery times and reduced discomfort.

For those throughout the UK seeking a definitive solution from an expert surgeon, Mr Dukic's practice is a national centre of excellence, combining high-volume experience with the latest, most effective treatments.

You can schedule an appointment with him for expert, bespoke advice through his Top Doctors profile or book an appointment through Harborne Hospital, HCA Healthcare, the Priory Hospital, Edgbaston, Circle Health Group or Droitwich Spa, Circle Health.

References

European Association of Urology. Urolithiasis: metabolic evaluation and recurrence prevention [Internet]. Arnhem (The Netherlands): European Association of Urology; 2024 [cited 2025 Aug 30]. Available from: https://uroweb.org/guidelines/urolithiasis/chapter/metabolic-evaluation-and-recurrence-prevention
Maalouf NM, Cameron MA, Moe OW, Sakhaee K. Low urine pH: a novel feature of the metabolic syndrome. Clin J Am Soc Nephrol. 2007;2(5):883–8.
Ong A, Brown G, Tokas T, Hameed BMZ, Philip J, Somani BK. Selection and outcomes for dissolution therapy in uric acid stones: a systematic review of literature. Curr Urol Rep. 2023;24(8):355–63.
British Association of Urological Surgeons. Urolithiasis [Internet]. London: BAUS; 2011. Available from: https://www.baus.org.uk
Spettel S, Shah P, Sekhar K, Herr A, White MD. Using Hounsfield unit measurement and urine parameters to predict uric acid stones. Urology. 2013;82(1):22–6.
Pak CYC, Sakhaee K, Fuller C. Successful management of uric acid nephrolithiasis with potassium citrate. Kidney Int. 1986;30(3):422–8.
Singh A, Alter HJ, Littlepage A. A systematic and comprehensive review of the literature: medical therapy for calculus disease. BJU Int. 2011;107(3):356–68.
Tiselius HG. Possibilities for preventing recurrent calcium stone formation: principles for the metabolic evaluation of patients with calcium stone disease. BJU Int. 2001;88(2):158–68.

Glossary for Patients

Alkalinising Agents: Medications (such as potassium citrate or sodium bicarbonate) used to raise the pH of your urine, making it less acidic so that uric acid stones can dissolve.
Ammoniagenesis: The process your kidneys use to remove acid (ammonium) from your body. When health issues like insulin resistance interfere with this, your urine becomes highly acidic, which encourages stones to form.
Calcium Oxalate: The most common type of kidney stone. Unlike uric acid stones, they are very dense, show up easily on X-rays, and cannot be dissolved with medication.
Computed Tomography (CT) Scan: A detailed medical imaging test. Doctors use a "non-contrast" CT scan to accurately spot uric acid stones and measure how dense they are.
Dissolution Therapy: A safe, non-surgical treatment where a patient takes daily medication to slowly break down and melt away uric acid kidney stones.
Gastrointestinal Disturbance: Stomach upset or digestive issues. This is the most common side effect of the medications used to dissolve kidney stones.
Hounsfield Units (HU): A scale used on CT scans to measure how dense (or hard) a kidney stone is. Uric acid stones have a low density (typically 350–500 HU), which helps doctors distinguish them from other stone types.
Metabolic Risk Factors / Insulin Resistance: Health conditions related to how your body processes sugar, weight, and energy (such as obesity and type 2 diabetes). These conditions can change your urine chemistry and greatly increase your risk of forming uric acid stones.
Purines: Natural substances found in certain foods, like red meat, organ meats, and some seafood. When your body digests purines, it produces uric acid.
Radiolucent: A medical term meaning an object does not show up clearly on a standard X-ray. Uric acid stones are typically radiolucent, which is why CT scans are needed to find them.
Uric Acid Nephrolithiasis: The formal medical term for the condition of having uric acid kidney stones.
Uric Acid Stones: A specific type of kidney stone that forms when your urine is too acidic. They make up about 10% of all kidney stones and are the only type that can be treated with dissolution therapy.
Urine Alkalinisation: The act of changing your urine chemistry to make it less acidic. This creates an environment where uric acid stones can no longer stay solid.
Urine pH: A measurement of how acidic your urine is. A low pH (usually below 5.5) means your urine is highly acidic—the perfect environment for uric acid stones to form.
Xanthine Oxidase Inhibitors (e.g., Allopurinol, Febuxostat): Specific medications that block the enzyme responsible for creating uric acid. By reducing how much uric acid your body produces, these drugs help dissolve active stones and prevent new ones from forming.