5 known interactions • 1 major • 3 moderate • 1 minor
Always disclose all medications to your healthcare providers — prescription medicines, OTC medications, vitamins, and herbal supplements. This list may not include every possible interaction. Use our Medicine Interaction Checker to screen your complete medication list.
Potentially life-threatening or causing permanent damage. Avoid combination.
May worsen condition or require dose adjustment. Monitor closely.
Usually limited clinical effect. Manage with routine monitoring.
Lithium
HCTZ reduces renal lithium clearance, potentially causing lithium toxicity. Volume depletion-induced increase in proximal tubular lithium reabsorption.
Management: Monitor lithium levels frequently when starting, stopping, or adjusting HCTZ. Reduce lithium dose if needed.
NSAIDs
NSAIDs antagonize the diuretic and antihypertensive effects of thiazides by causing sodium retention.
Management: Monitor blood pressure and renal function.
Digoxin
Thiazide-induced hypokalemia potentiates digoxin toxicity (hypokalemia increases binding of digoxin to Na+/K+ATPase).
Management: Monitor serum potassium and digoxin levels; maintain K+ >4.0 mEq/L in patients on digoxin.
Antidiabetic agents (insulin, sulfonylureas)
Thiazides may increase blood glucose. Antidiabetic doses may need adjustment.
Management: Monitor blood glucose; adjust antidiabetic therapy as needed.
Allopurinol
HCTZ increases uric acid levels, potentially reducing allopurinol effectiveness and precipitating gout.
Always ask your pharmacist about potential interactions with food, alcohol, and supplements specific to Hydrochlorothiazide. Some medicines have significant interactions with grapefruit juice, high-fat meals, dairy products, or vitamin K-rich foods.