Drug interactions
Calcium citrate + Hydrochlorothiazide
Severity: Moderate
Calcium citrate and Hydrochlorothiazide: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Thiazide diuretics lower urinary calcium excretion, so taking calcium supplements alongside them can raise serum calcium. Hypercalcemia and, with alkaline calcium salts such as citrate, metabolic alkalosis (milk-alkali picture) may occur, mainly with high calcium doses or reduced kidney function.
What this interaction means in plain words
Calcium citrate and Hydrochlorothiazide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Thiazides enhance distal tubular calcium reabsorption, reducing renal calcium clearance, while citrate adds an alkali load.
What to do
Check serum calcium periodically, especially at the start of therapy or after dose changes, and reduce the calcium supplement dose if hypercalcemia develops. Take extra care in patients with renal impairment or high-dose calcium and vitamin D use.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Hydrochlorothiazide
Frequently asked questions
Can I take Calcium citrate with Hydrochlorothiazide?
MediHelp rates the interaction as moderate. Calcium citrate and Hydrochlorothiazide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Thiazide diuretics lower urinary calcium excretion, so taking calcium supplements alongside them can raise serum calcium. Hypercalcemia and, with alkaline calcium salts such as citrate, metabolic alkalosis (milk-alkali picture) may occur, mainly with high calcium doses or reduced kidney function.
How serious is the interaction between Calcium citrate and Hydrochlorothiazide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check serum calcium periodically, especially at the start of therapy or after dose changes, and reduce the calcium supplement dose if hypercalcemia develops. Take extra care in patients with renal impairment or high-dose calcium and vitamin D use.
What other medicines interact with Hydrochlorothiazide?
MediHelp also lists interactions of Hydrochlorothiazide with, for example, Dofetilide, Amifostine, Amiodarone. The full list is on the Hydrochlorothiazide page.
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