Hydrochlorothiazide and Calcitriol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Hydrochlorothiazide
Calcitriol
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased serum calcium levels resulting in hypercalcemia
Interaction Deep Dive
In some reports, concomitant use of calcitriol and a thiazide diuretic has resulted in hypercalcemia. Thiazide diuretics have been shown to induce hypercalcemia by a reduction of calcium excretion in the urine. Therefore, if coadministration of calcitriol and a thiazide diuretic is necessary, caution should be used321.
Why it happens (mechanism)
Reduction of calcium excretion in the urine by the thiazide diuretic
Common questions
Can I take Hydrochlorothiazide and Calcitriol together?
Increased serum calcium levels resulting in hypercalcemia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Hydrochlorothiazide and Calcitriol interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Hydrochlorothiazide or Calcitriol need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (3)
- Product Information: calcitriol oral solution, calcitriol oral solution. Roxane Laboratories,Inc, Columbus, OH, 2005. DailyMed
- Product Information: calcitriol oral capsules, calcitriol oral capsules. Teva Pharmaceuticals USA, Sellersville, PA, 2006. DailyMed
- Product Information: VECTICAL(R) topical ointment, calcitriol topical ointment. Galderma Laboratories, LP, Fort Worth, TX, 2009. DailyMed
Keep reading about Hydrochlorothiazide
Keep reading about Calcitriol
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist