Most kidney stones smaller than 5 mm pass on their own with nothing more than fluids, pain relief, and time. Stones larger than that typically need medical help to break apart or remove. The treatment you get depends almost entirely on two things: the size of the stone and where it’s stuck.
Passing a Small Stone at Home
Stones under 4 mm generally pass within one to two weeks. Stones between 4 and 5 mm still have a reasonable chance of passing but may take longer. During this waiting period, the goal is to stay hydrated, manage the pain, and watch for signs that the stone isn’t moving. If a stone in the ureter hasn’t passed after two to four weeks of observation, your doctor will likely refer you to a urologist to discuss next steps.
You may have heard that a medication called tamsulosin (originally designed for prostate issues) can relax the ureter and help stones pass faster. Doctors have prescribed it off-label for years. However, a rigorous double-blind trial published in JAMA Internal Medicine found that tamsulosin did not significantly increase the passage rate compared to placebo for stones under 9 mm. Some urologists still prescribe it, particularly for larger stones in the lower ureter, but the evidence is weaker than many people assume.
Managing the Pain
Kidney stone pain, called renal colic, can be among the most intense pain people experience. Anti-inflammatory drugs like ibuprofen and naproxen are the first-line treatment, and they actually work better than opioids for this specific type of pain. That’s because the pain comes largely from inflammation and spasm in the ureter, which anti-inflammatories target directly.
If over-the-counter options aren’t enough, stronger anti-inflammatories can be given by injection in an emergency department. Opioid painkillers are reserved for situations where anti-inflammatories aren’t working or can’t be used safely, such as in people with kidney disease or stomach ulcers. Combining both types of medication at lower doses can sometimes provide better relief with fewer side effects than using either alone.
Shock Wave Lithotripsy
For stones that won’t pass on their own but aren’t enormous, shock wave lithotripsy (often called ESWL) is the least invasive procedural option. You lie on a table while a machine sends focused sound waves through your body to break the stone into smaller fragments that you then pass naturally over the following days or weeks.
Success rates vary widely, from about 30% to 90%, depending on where the stone sits and how hard it is. Stones in certain parts of the kidney or the upper ureter respond best. Stones that are very dense (like those made of calcium oxalate monohydrate) or larger than about 2 cm are poor candidates. The procedure is typically done as an outpatient, meaning you go home the same day. You’ll likely feel sore in the area where the waves entered, and you should expect to see blood in your urine for a few days as fragments pass.
Ureteroscopy
When a stone is lodged in the ureter or shock wave therapy isn’t a good fit, ureteroscopy is the most common alternative. A thin, flexible scope is passed through the urethra, up through the bladder, and into the ureter. Once the surgeon can see the stone, a laser breaks it into tiny pieces that are either extracted with a small basket or left to pass on their own.
A Cochrane review comparing the two approaches found that ureteroscopy achieves higher stone-free rates than shock wave lithotripsy. The tradeoff is a slightly higher complication rate and a longer hospital stay, roughly two to three extra days on average in studies that compared them directly. In practice, many ureteroscopies in the U.S. are done as outpatient or overnight procedures, so your actual experience may differ from older trial data.
After ureteroscopy, your surgeon will often place a temporary ureteral stent, a thin tube running from the kidney to the bladder, to keep the ureter open while swelling goes down. This is worth knowing about in advance because stent side effects are extremely common. Up to 80% of people with stents experience bladder irritation, frequent urination, pain or burning when peeing, blood in the urine, or a pulling sensation in the pelvis. Most stents stay in for a few days to a few weeks and are removed in a quick office procedure.
Surgery for Large or Complex Stones
Stones larger than 20 mm, or branching “staghorn” stones that fill part of the kidney’s drainage system, typically require a procedure called percutaneous nephrolithotomy. A surgeon makes a small incision in your back and passes a scope directly into the kidney to break up and remove the stone. This is a more involved operation, usually requiring general anesthesia and a hospital stay of one to several days, but it’s the most effective way to clear large stone burdens in a single session.
Open surgery to remove kidney stones is rare today. It’s reserved for unusual anatomy or situations where other approaches have failed.
When a Stone Becomes an Emergency
Most kidney stones are painful but not dangerous. The situation changes when a stone blocks the ureter and an infection develops behind it. This combination can escalate to life-threatening sepsis quickly. Warning signs include fever, chills, nausea or vomiting alongside the typical flank pain, or feeling generally unwell in a way that goes beyond the pain itself.
In these cases, the priority shifts away from removing the stone and toward draining the kidney urgently. Surgeons place either a ureteral stent or a drainage tube through the back directly into the kidney. Trying to surgically remove a stone when there’s an active, untreated infection behind it can actually push bacteria into the bloodstream, so doctors address the drainage and start antibiotics first. The stone itself gets dealt with later, once the infection is under control.
Preventing the Next Stone
About half of people who form one kidney stone will form another within five to ten years, so prevention matters. The single most effective step is drinking enough fluid to produce at least 2 to 2.5 liters of urine per day. Water is the simplest choice.
Beyond hydration, prevention depends on what your stones are made of. If you’ve passed a stone, try to catch it (your doctor may give you a strainer) so it can be analyzed. For the most common type, calcium oxalate stones, dietary changes include reducing sodium intake, eating moderate rather than excessive amounts of animal protein, and getting adequate calcium from food (counterintuitively, too little dietary calcium increases stone risk). Your doctor may also prescribe potassium citrate, a medication that makes urine less acidic and inhibits crystal formation. For people who form stones repeatedly, a type of blood pressure medication called a thiazide diuretic can reduce the amount of calcium your kidneys excrete into the urine.
A 24-hour urine collection, where you save all your urine for a full day so it can be analyzed, gives the clearest picture of your specific risk factors and helps guide which preventive strategies will work best for you.