Thiazide Diuretics and Gout: What You Need to Know About Uric Acid Risks

If you're taking a thiazide diuretic like hydrochlorothiazide for high blood pressure, you might not realize it could be raising your risk of gout. It’s not a common side effect for everyone, but for some people, especially those with a history of high uric acid or past gout attacks, this medication can trigger painful flare-ups. The connection isn’t guesswork-it’s backed by decades of research and clinical data. And if you’re one of the 50 million Americans prescribed a thiazide each year, understanding this link could help you avoid unnecessary pain and extra medications.

How Thiazide Diuretics Raise Uric Acid Levels

Thiazide diuretics, including hydrochlorothiazide and chlorthalidone, work by making your kidneys flush out more sodium and water. That lowers blood pressure. But here’s the catch: they also mess with how your kidneys handle uric acid. Uric acid is a waste product from breaking down purines in food. Normally, your kidneys filter it out and send it through urine. But thiazides interfere with that process.

Research shows these drugs compete with uric acid for transporters in the kidney, especially OAT1 and OAT4. When thiazides latch onto these transporters, uric acid gets trapped in the bloodstream instead of being excreted. The result? Your serum uric acid levels can rise 6% to 21% within just a few days of starting the drug. This isn’t a slow build-it happens fast. And if your levels cross 6.8 mg/dL, the point where uric acid starts crystallizing, you’re at risk for gout.

Who’s Most at Risk?

Not everyone who takes a thiazide gets gout. But certain people are far more likely to. If you already have high uric acid (above 7.0 mg/dL for men, 6.0 mg/dL for women), a past gout attack, or kidney problems, your risk jumps. Genetics matter too. Some people naturally reabsorb more uric acid in their kidneys, and thiazides make that worse.

Studies show the longer you take thiazides, the higher your risk. After 180 days of use, the chance of needing gout medication rises by 41% compared to the first month. That’s not a small increase. And it’s not just about the drug-it’s about timing. Many people start taking allopurinol or colchicine months after beginning thiazides, not because their gout got worse, but because the medication itself triggered it. This is called a prescribing cascade: one drug causes a problem that leads to another drug, which might not be needed if the original trigger was avoided.

Thiazides vs. Other Diuretics

Not all diuretics are the same when it comes to gout. Loop diuretics like furosemide carry an even higher risk than thiazides. But among thiazides themselves, there’s a myth that chlorthalidone is worse than hydrochlorothiazide. Recent studies say that’s not true. At similar doses, both drugs raise uric acid about the same. So switching from one to the other won’t solve the problem if you’re already at risk.

On the flip side, potassium-sparing diuretics like spironolactone don’t raise uric acid at all. In fact, they might even help lower it slightly. That makes them a smart alternative for people with both high blood pressure and a history of gout.

What Does Gout Look Like When It’s Triggered by Thiazides?

There’s nothing special about gout caused by thiazides. It looks exactly like any other gout attack: sudden, intense pain in one joint-usually the big toe. The joint swells, turns red, and feels hot to the touch. It often hits at night and can be so painful you can’t even tolerate a bedsheet touching it. Blood tests will show uric acid above 6.8 mg/dL in about 90% of cases. But here’s the twist: some people have high uric acid without symptoms, and others get attacks even with normal levels. That’s why doctors don’t rely on blood tests alone to diagnose gout-they look at the symptoms and sometimes use imaging or joint fluid tests.

What Should You Do If You’re on Thiazides?

If you’re taking a thiazide and have never had gout, you don’t need to panic. Only 1-2% of people on these drugs develop gout. But if you have risk factors-like high uric acid, obesity, heavy alcohol use, or a family history of gout-you should talk to your doctor. The American College of Cardiology recommends checking your uric acid level before starting thiazides if you have any of these risk factors. That simple step can prevent a lot of trouble down the road.

If you’ve already had a gout attack and your doctor wants to keep you on a thiazide, they should also prescribe a urate-lowering drug like allopurinol. The European League Against Rheumatism recommends keeping uric acid below 6.0 mg/dL to prevent crystals from forming. Lifestyle changes matter too: cut back on beer, red meat, shellfish, and sugary drinks. Losing even 5-10% of your body weight can cut your gout risk in half.

Alternatives to Thiazides That Don’t Raise Uric Acid

You don’t have to stay on thiazides if they’re causing problems. There are other blood pressure medications that won’t raise uric acid-and some might even help lower it.

• Losartan: This is an ARB, a type of blood pressure drug that blocks angiotensin II. Unlike other ARBs, losartan also blocks the URAT1 transporter in the kidney, which helps your body get rid of more uric acid. It’s a double win: lowers blood pressure and uric acid.
• Calcium channel blockers: Drugs like amlodipine and diltiazem don’t affect uric acid at all. They’re just as effective as thiazides for lowering blood pressure.
• Spironolactone: This potassium-sparing diuretic doesn’t interfere with uric acid excretion. It’s especially useful if you have heart failure or resistant hypertension.

Yes, some of these alternatives cost more. Generic hydrochlorothiazide runs about $4 for 90 pills. Losartan and amlodipine are also cheap generics now, but prices vary. Still, if you’re spending hundreds a year on gout meds because of thiazide-induced flare-ups, switching might save you money in the long run.

The Bigger Picture: Blood Pressure vs. Gout

Here’s the tricky part: high blood pressure and gout are linked in both directions. People with high blood pressure are nearly twice as likely to get gout. And people with high uric acid are more likely to develop high blood pressure. That makes it hard to tell what’s causing what in some cases. But the evidence is clear: thiazides add fuel to the fire. They don’t just coincide with gout-they actively raise the risk.

That’s why major guidelines now say: don’t use thiazides alone if you have gout or uric acid over 8.0 mg/dL. If you must use them, pair them with a urate-lowering drug. The cardiovascular benefits of controlling blood pressure are real-heart attacks and strokes are serious. But so is chronic joint damage from repeated gout attacks. The goal isn’t to avoid thiazides entirely. It’s to use them wisely.

What’s Next for Thiazides?

Researchers are working on new diuretics that lower blood pressure without messing with uric acid. A new drug in Phase II trials (NCT04892105) targets only the sodium-chloride cotransporter in the kidney, avoiding the OAT transporters that move uric acid. Results aren’t expected until late 2025, but if it works, it could change how we treat hypertension in people with gout.

In the meantime, the best approach is awareness. If you’re on a thiazide and have any risk factors for gout, ask your doctor about your uric acid level. If you’ve had a gout attack since starting the drug, don’t assume it’s just bad luck. Ask if the medication could be the cause-and whether a safer alternative exists.