MAJOR — Use With Caution
FDA-documented interaction. Thiazide diuretics are specifically called out on lithium label. Lithium dose reduction of 25-50% may be needed. Loop diuretics may be less problematic.
Evidence level: STRONG
Hydrochlorothiazide (a water pill for blood pressure) can raise lithium levels by 25-40% because when your kidneys reabsorb more sodium (due to the diuretic), they also reabsorb more lithium.
Thiazide diuretics reduce renal lithium clearance by increasing proximal tubular reabsorption of lithium (compensatory sodium and lithium reabsorption). Can increase lithium levels by 25-40%. FDA lithium label warns about thiazide diuretics.
If you take lithium and are prescribed HCTZ, expect your lithium dose to need reduction. Get frequent blood tests initially. Maintain consistent fluid and salt intake.
Take Lithium and Hydrochlorothiazide as prescribed by your healthcare provider. If both are taken daily, maintain consistent timing for each. When picking up a new prescription, always ask your pharmacist to review your full medication list for timing conflicts.
Higher risk for: elderly, those with liver or kidney impairment, polypharmacy (5+ medications), recent medication changes, or those with multiple chronic conditions. Consult your pharmacist for specific risk factors.
Increased tremor, nausea, vomiting, diarrhea, confusion, drowsiness, dehydration symptoms, muscle weakness
Request lithium level monitoring. Discuss alternative antihypertensives (amlodipine, ARBs may have less effect). If thiazide is necessary, plan lithium dose reduction.
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Hydrochlorothiazide (a water pill for blood pressure) can raise lithium levels by 25-40% because when your kidneys reabsorb more sodium (due to the diuretic), they also reabsorb more lithium.
Take Lithium and Hydrochlorothiazide as prescribed by your healthcare provider. If both are taken daily, maintain consistent timing for each. When picking up a new prescription, always ask your pharmacist to review your full medication list for timing conflicts.
Increased tremor, nausea, vomiting, diarrhea, confusion, drowsiness, dehydration symptoms, muscle weakness
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Request lithium level monitoring. Discuss alternative antihypertensives (amlodipine, ARBs may have less effect). If thiazide is necessary, plan lithium dose reduction.
Or browse the full interaction database (121,000+ pairs).