Kidney stones, also known as renal calculi, are solid masses made of crystals that form in the kidneys from substances in the urine. Kidney stones can cause severe pain, bleeding, infection, and blockage of urine flow. While some people are more prone to developing kidney stones due to genetic factors, certain medications can also increase one’s risk.
Medications that Cause Kidney Stones
Several types of medications have been associated with increased kidney stone risk. The most common include:
Diuretics
Diuretics, sometimes called “water pills,” are medications that increase urine output. They work by making the kidneys excrete more sodium in the urine, which pulls water along with it through osmosis. This decreases overall fluid volume in the body. Diuretics are often prescribed to treat high blood pressure, heart failure, and swelling.
Common diuretics that may contribute to kidney stones include:
- Furosemide (Lasix)
- Hydrochlorothiazide
- Chlorthalidone
- Indapamide
These medications can cause kidney stones by increasing urinary calcium excretion. They may also raise uric acid levels in the urine, leading to uric acid stones.
Calcium-based Antacids
Antacids containing calcium, such as Tums and Rolaids, provide supplemental calcium to help neutralize stomach acid. The excess calcium is usually excreted through urine. High levels of calcium in the urine increase the risk of calcium phosphate or calcium oxalate stone formation.
Topiramate
Topiramate (Topamax) is an anticonvulsant medication used to treat epilepsy and migraine headaches. One of its side effects is an increased risk of kidney stone formation. Topiramate increases urinary pH, leading to increased urinary calcium precipitation. The drug has also been associated with impaired kidney function.
Carbonic Anhydrase Inhibitors
Acetazolamide (Diamox) is a carbonic anhydrase inhibitor that is sometimes used for glaucoma, epilepsy, altitude sickness, and heart failure. It works by decreasing bicarbonate reabsorption in the kidneys, leading to increased urinary citrate and pH. These changes can promote calcium phosphate crystallization and kidney stone formation in susceptible individuals.
Protease Inhibitors
Protease inhibitors are antiretroviral medications used to treat HIV and AIDS. Indinavir (Crixivan) and atazanavir (Reyataz) have been associated with increased kidney stone risk. Protease inhibitors can cause urinary crystallization by increasing urinary pH and calcium excretion while decreasing citrate.
Sulfonylureas
Sulfonylureas, including glimepiride (Amaryl) and glyburide (Micronase), are oral medications used to stimulate insulin secretion in people with type 2 diabetes. They may contribute to kidney stone formation by producing acidic urine, decreasing urinary citrate excretion, and increasing calcium stone risk.
Vitamin C Supplements
High-dose vitamin C supplementation has been linked to kidney stones in some individuals. Vitamin C is metabolized to oxalate, which binds to calcium to form calcium oxalate stones. People who take vitamin C in excess of 1000 mg per day may have increased oxalate production.
Triamterene
Triamterene (Dyrenium) is a potassium-sparing diuretic used with other medications for high blood pressure and swelling. It has been associated with the formation of triamterene-containing kidney stones, which often require surgical removal.
Ephedrine
Ephedrine is a stimulant that was historically used for asthma, narcolepsy, and weight loss. It increases urinary calcium excretion, decreases citrate, and makes urine more alkaline. These factors create an environment in the kidneys that promotes kidney stone formation.
Mechanisms of Kidney Stone Formation
Medications can trigger kidney stones through various mechanisms, such as:
- Increased urinary calcium – Higher calcium levels in the urine lead to increased calcium oxalate and calcium phosphate supersaturation.
- Decreased urinary citrate – Citrate normally binds with calcium and inhibits stone formation. Low citrate increases free calcium.
- Increased uric acid – Some drugs elevate uric acid levels in the urine, leading to uric acid stones.
- Alkaline urine – Medications that alkalinize the urine promote calcium phosphate stones.
- Acidic urine – Acidic urine environments encourage uric acid stones.
- Crystallization inhibitors – Protease inhibitors reduce inhibitors of calcium oxalate crystallization.
- Impaired kidney function – Poor kidney function reduces the excretion of stone-forming salts.
Risk Factors for Medication-Related Kidney Stones
Certain individuals have a higher risk of developing kidney stones from medications, including:
- People with a history of kidney stones
- Individuals with chronic kidney disease
- Those with inflammatory bowel disease like Crohn’s or ulcerative colitis
- People who have undergone gastric bypass surgery
- Individuals with gout
- Those immobilized due to spinal cord injury
- Astronauts and others exposed to extended weightlessness
- People with certain genetic disorders like cystinuria
Additional risk factors include low fluid intake, high sodium diet, high protein intake, hypercalciuria, and hyperuricosuria. Kidney stone formation may be reduced by avoiding causative medications if possible, along with increased hydration and medical management.
Symptoms of Kidney Stones
Kidney stones usually cause the following signs and symptoms:
- Severe pain in the side and back, below the ribs
- Pain that spreads to the lower abdomen and groin
- Pain that comes in waves and fluctuates in intensity
- Pain on urination
- Pink, red or brown urine from blood
- Cloudy or foul-smelling urine
- Persistent need to urinate
- Urinating more often than usual
- Fever and chills
- Nausea and vomiting
Kidney stones usually cause severe pain that comes in waves. The pain often starts suddenly as the stone moves down the urinary tract, causing irritation and blockage. Medical attention should be sought immediately if kidney stone symptoms occur.
Diagnosing Kidney Stones
Kidney stones are diagnosed through various tests, such as:
- Medical history – Healthcare providers ask about symptoms, risk factors, and family history of kidney stones.
- Physical exam – Tenderness may occur when the abdomen is pressed over the stone location.
- Urinalysis – Microscopy can detect red blood cells, white blood cells, and crystals indicating kidney stones.
- Blood tests – Blood work helps assess kidney function and look for high calcium, uric acid, and other stone-forming chemicals.
- Imaging tests – CT scans, ultrasounds, and X-rays help locate kidney stones.
- Urine culture – A culture determines if a urinary tract infection is also present.
Identifying the stone type helps guide treatment and preventative recommendations. Patients should provide a comprehensive medication list to their healthcare provider.
Treatment for Medication-Related Kidney Stones
Treatment options for medication-induced kidney stones include:
Pain Control
Over-the-counter NSAIDs like ibuprofen help relieve mild discomfort. For moderate to severe pain, stronger prescription painkillers are used. Patient-controlled analgesia pumps allowing self-administration of intravenous narcotics are often required.
Alpha-blockers
Alpha-blocker medications like tamsulosin (Flomax) relax the muscles of the ureter, helping small stones pass more easily. They are used to try passing stones less than 5 mm.
Calcium Channel Blockers
Calcium channel blockers like nifedipine also relax ureteral smooth muscle to facilitate stone passage but are not as effective as alpha blockers.
Lithotripsy
Extracorporeal shock wave lithotripsy uses acoustic shock waves administered outside the body to break up larger kidney stones. The smaller pieces can then pass down the ureter more easily. No incision is required.
Ureteroscopy
In ureteroscopy, a small ureteroscope is inserted into the urethra and up the ureter. A laser, ultrasound or mechanical device breaks the stone into sludge that is suctioned out. Stents may temporarily be left in place.
Percutaneous Nephrolithotomy
This surgery entails making a small incision in the back to directly access larger stones inside the kidney. Instruments break up the stone, and the pieces are then suctioned out.
Open Surgery
Open surgery is rarely done nowadays unless the kidney stone is extremely large and other procedures are not possible. An incision is made into the kidney to remove the stone.
Dietary Changes
Eating more citrus fruits and vegetables adds citrate to urine. A low-sodium, low-protein diet helps reduce calcium and uric acid levels. Drinking 2-3 liters of fluid daily dilutes the concentration of stone-forming salts.
Medication Changes
Substituting a problematic medication for an alternative class without the same side effects can lower future kidney stone risk. Additionally, medications may be prescribed to change urine acidity, reduce calcium, or prevent certain crystals.
Preventing Recurrence of Medication-Induced Kidney Stones
Recurrent kidney stones may be avoided by:
- Following all dietary and medication prevention instructions
- Identifying any underlying medical conditions
- Undergoing metabolic testing to assess urine composition
- Discontinuing causative medications if possible
- Taking prescribed medications to block stone formation
- Considering prostate removal surgery for men with recurrent stones
- Treating struvite stones aggressively to prevent recurrence
- Following up regularly with a urologist or nephrologist
Kidney stones often reoccur within 5-10 years without preventative measures. Medication-induced kidney stones may continue forming if the offending drug is not stopped. Lifelong prevention is key after an initial stone occurrence.
Conclusion
Certain medications like diuretics, calcium-based antacids, topiramate, and vitamin C can increase the risk of calcium oxalate, calcium phosphate, and uric acid kidney stones. High urinary calcium, decreased citrate, acidic urine, and impaired kidney function are some mechanisms by which drugs promote stone formation. Those with a history of kidney stones are at greatest risk. Severe flank pain is the hallmark symptom requiring prompt medical attention. Treatment options range from pain control to shock wave lithotripsy or ureteroscopy for stone removal. Preventing recurrence requires dietary changes, discontinuing causative medications, metabolic testing, and follow-up care. Being aware of drugs that may cause kidney stones allows patients and health providers to minimize risks through monitoring and preventative strategies.