Drug interactions
Calcitriol + Rifampin
Severity: Moderate
Calcitriol and Rifampin: 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
Rifampin is a potent enzyme inducer and increases the metabolism of vitamin D and its active metabolites. Calcitriol exposure may fall, leading to reduced effect and possible hypocalcemia or osteomalacia during long-term use.
What this interaction means in plain words
Calcitriol and Rifampin 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
Rifampin induces CYP3A4 and other enzymes, accelerating calcitriol catabolism.
What to do
Monitor serum calcium, phosphate and PTH during rifampin therapy and after discontinuation. Raise the calcitriol dose as needed and reduce it again when rifampin is stopped.
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 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 Rifampin?
MediHelp rates the interaction as moderate. Calcitriol and Rifampin 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. Rifampin is a potent enzyme inducer and increases the metabolism of vitamin D and its active metabolites. Calcitriol exposure may fall, leading to reduced effect and possible hypocalcemia or osteomalacia during long-term use.
How serious is the interaction between Calcitriol and Rifampin?
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, phosphate and PTH during rifampin therapy and after discontinuation. Raise the calcitriol dose as needed and reduce it again when rifampin is stopped.
What other medicines interact with Calcitriol?
MediHelp also lists interactions of Calcitriol with, for example, Amlodipine-hydrochlorothiazide-valsartan, Amlodipine-olmesartan-hydrochlorothiazide, Amobarbital. The full list is on the Calcitriol page.
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