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| Possible Interactions with: Vitamin D |
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| Also listed as: Calciferol; Calcitrol;
Cholecalciferol; Ergocalciferol |
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If you are currently being treated with any of the following medications, you
should not use vitamin D supplements without first talking to your healthcare
provider. Vitamin D levels may be increased by the following
medications: - Estrogen: Hormone replacement therapy with estrogen appears to
increase vitamin D levels in the blood; this may have a beneficial effect on
calcium and bone metabolism. In addition, use of vitamin D supplements in
conjunction with estrogen replacement therapy (ERT) increases bone mass more
than ERT alone. However, this benefit may be lost with the addition of
progesterone.
- Isoniazid (INH): INH, a medication used to treat tuberculosis,
may raise blood levels of vitamin D.
- Thiazide: Diuretics in this class (such as hydrochlorothiazide)
increase the activity of vitamin D and can lead to inappropriately high calcium
levels in the blood.
Vitamin D levels may be decreased, or its absorption may be reduced, by the
following medications: - Antacids: Taking certain antacids for long periods of time may
alter the levels, metabolism, and availability of vitamin D.
- Calcium-channel blockers (such as verapamil): These medications
are used to treat high blood pressure and heart conditions may decrease the
production of vitamin D by the body.
- Cholestyramine: This cholesterol-lowering medication, known as
a bile acid sequestrant, interferes with the absorption of vitamin D (as well as
other fat soluble vitamins).
- Phenobarbital, phenytoin, and other anticonvulsant medications:
These medications may accelerate the body's use of vitamin D.
- Mineral oil also interferes with absorption.
In addition, Vitamin D may enhance the effects of doxorubicin, a
medicine used to treat a variety of cancers. More research is needed. Some clinicians recommend following calcium levels closely if vitamin D is
taken with digoxin, a medication used to treat irregular heart rhythms.
This is because vitamin D improves absorption of calcium. Calcium, in turn, can
increase the likelihood of a toxic reaction from this medication. Weight Loss Products
Orlistat, a medication used for weight
loss and olestra, a substance added to certain food products, are both intended
to bind to fat and prevent the absorption of fat and the associated calories.
Because of their effects on fat, orlistat and olestra may also prevent the
absorption of fat-soluble vitamins such as vitamin D. Given this concern and
possibility, the Food and Drug Administration (FDA) now requires that vitamin D
and other fat soluble vitamins (namely, A, E, and K) be added to food products
containing olestra. How well vitamin D from such food products is absorbed and
used by the body is not clear. In addition, physicians who prescribe orlistat
add a multivitamin with fat soluble vitamins to the
regimen. |
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| Drug Interactions |
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Copyright © 2004 A.D.A.M., Inc
The publisher does not accept any responsibility for the accuracy of
the information or the consequences arising from the application, use, or misuse
of any of the information contained herein, including any injury and/or damage
to any person or property as a matter of product liability, negligence, or
otherwise. No warranty, expressed or implied, is made in regard to the contents
of this material. No claims or endorsements are made for any drugs or compounds
currently marketed or in investigative use. This material is not intended as a
guide to self-medication. The reader is advised to discuss the information
provided here with a doctor, pharmacist, nurse, or other authorized healthcare
practitioner and to check product information (including package inserts)
regarding dosage, precautions, warnings, interactions, and contraindications
before administering any drug, herb, or supplement discussed
herein.
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