Can chlorthalidone cause gout flares?

Chlorthalidone and Gout Flares

Yes, chlorthalidone can cause gout flares due to its effect on increasing serum uric acid levels. Multiple guidelines recognize this association and recommend caution when using chlorthalidone in patients with a history of gout.

Mechanism and Evidence

Chlorthalidone, like other thiazide and thiazide-like diuretics, can precipitate hyperuricemia and gout flares through several mechanisms:

• The FDA drug label specifically warns that "hyperuricemia may occur or frank gout may be precipitated in certain patients receiving chlorthalidone" 1
• The American Heart Association recommends using chlorthalidone with caution in patients with a history of gout 2
• The 2020 American College of Rheumatology guideline for gout management conditionally recommends switching from hydrochlorothiazide (which has similar effects to chlorthalidone) to an alternate antihypertensive when feasible for patients with gout 3

Clinical Significance

The impact of chlorthalidone on gout risk is clinically significant:

• In the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), patients assigned to chlorthalidone had a higher risk of developing gout compared to those on amlodipine (37% higher risk) or lisinopril (15% higher risk) 4
• The risk of gout with chlorthalidone appears to increase after the first year of treatment 4
• Hyperuricemia risk from chlorthalidone is dose-dependent, with higher doses (>25 mg) carrying greater risk 2

Management Strategies for Patients Requiring Chlorthalidone

If a patient with gout or hyperuricemia requires chlorthalidone for hypertension management:

1. Use the lowest effective dose (typically 12.5-25 mg daily) to minimize hyperuricemia risk 2
2. Consider alternative antihypertensives when appropriate:
   • Amlodipine has been shown to lower gout risk compared to chlorthalidone 4
   • Losartan is conditionally recommended as a preferred antihypertensive for patients with gout due to its uricosuric effects 3
3. Monitor serum uric acid levels periodically to detect hyperuricemia before it progresses to clinical gout 1
4. Provide dietary counseling to reduce other gout risk factors:
   • Limit alcohol (especially beer and spirits)
   • Reduce intake of sugar-sweetened drinks, fructose, meat, and seafood
   • Encourage low-fat dairy products 3

Special Considerations

• The combination of chlorthalidone with urate-lowering therapy may be necessary in patients who must remain on this diuretic
• Prophylactic therapy with low-dose colchicine or NSAIDs may be considered in high-risk patients starting chlorthalidone who cannot use alternative antihypertensives 3
• The risk of gout flares must be balanced against chlorthalidone's proven benefits in hypertension management, particularly in resistant hypertension 3

In summary, while chlorthalidone is an effective antihypertensive with particular benefits in certain populations, its use comes with a clear risk of hyperuricemia and gout flares that should be considered in clinical decision-making, especially in patients with a history of gout or elevated uric acid levels.