Drug interactions
Calcitriol + Metolazone
Severity: Moderate
Calcitriol and Metolazone: 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-like diuretics reduce urinary calcium excretion, and calcitriol increases calcium absorption, so together they can cause hypercalcaemia. The risk is greatest with oral or injectable calcitriol, high doses or renal impairment.
What this interaction means in plain words
Calcitriol and Metolazone 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.
Calcitriol belongs to Musculoskeletal; Metolazone belongs to Cardiovascular.
Why it happens
Additive effect on serum calcium: metolazone reduces renal calcium excretion while calcitriol increases intestinal calcium absorption and bone mobilisation.
What to do
Monitor serum calcium periodically and reduce the calcitriol dose or stop the diuretic if hypercalcaemia occurs.
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 Metolazone
Other interactions of Calcitriol
- Amlodipine-hydrochlorothiazide-valsartan + Calcitriol Moderate
- Amlodipine-olmesartan-hydrochlorothiazide + Calcitriol Moderate
- Amobarbital + Calcitriol Moderate
- Apalutamide + Calcitriol Moderate
- Atazanavir + Calcitriol Moderate
- Atenolol-chlorthalidone + Calcitriol Moderate
Frequently asked questions
Can I take Calcitriol with Metolazone?
MediHelp rates the interaction as moderate. Calcitriol and Metolazone 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-like diuretics reduce urinary calcium excretion, and calcitriol increases calcium absorption, so together they can cause hypercalcaemia. The risk is greatest with oral or injectable calcitriol, high doses or renal impairment.
How serious is the interaction between Calcitriol and Metolazone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor serum calcium periodically and reduce the calcitriol dose or stop the diuretic if hypercalcaemia occurs.
What other medicines interact with Metolazone?
MediHelp also lists interactions of Metolazone with, for example, Amifostine, Amlodipine-hydrochlorothiazide-valsartan, Amlodipine-olmesartan-hydrochlorothiazide. The full list is on the Metolazone page.
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