|
Calcium Supplements
Medications that
reduce stomach
acid can interfere
with absorption
of calcium.
Claudia Wober, BSc(Pharm), BFA
Drug and Poison Information
Centre, Vancouver
Many people do not obtain enough calcium in their diet and need
to take calcium
supplements to ensure adequate intake and to build and maintain
healthy bones. Calcium supplements are sold as various “salts” in
which the amount of elemental calcium varies. For example, a
1250 mg tablet of calcium carbonate contains only 500 mg of elemental
calcium. A person taking one such tablet each day might think
they are meeting or exceeding their daily requirement for elemental
calcium (1000 to 1500 mg/day). In fact, they would only be getting
500 mg of elemental calcium and, depending on their diet, may
not be getting enough of this essential mineral. Always check
the amount of elemental calcium in a product and consult your
pharmacist if unsure.
The body can only absorb a portion of the calcium ingested at
one time. For this reason it is better to take doses of up to
500 mg of calcium at different times of the day.
Calcium supplements are best taken with meals to ensure that
the calcium is absorbed. Calcium carbonate must be exposed to
acid in the stomach to dissolve. If not taken with food, which
stimulates production of stomach acid, the calcium may not dissolve
and won’t be absorbed from the gut. Undissolved calcium
carbonate may cause bloating and constipation. Talk to your pharmacist
if you take calcium tablets and experience these symptoms.
Calcium citrate does not need stomach acid to dissolve and may
be taken without food. Calcium citrate is generally more expensive
than calcium carbonate and larger quantities of calcium citrate
must be taken to get the same amount of elemental calcium (1000
mg of calcium citrate contains 211 mg of elemental calcium).
Medications that reduce stomach acid can interfere with absorption
of calcium. These include medicines used for stomach ulcers or
gastroesophageal reflux (e.g., omeprazole, ranitidine and many
others). Talk to your pharmacist if you take a stomach medicine
and need to take a calcium supplement.
Calcium can interfere with the effects of some medicines by
preventing absorption of the drug. These include some, but not
all, antibiotics (e.g., ciprofloxacin) and iron supplements.
If your pharmacist knows that you take calcium supplements he
or she can check to see if there is a problem and provide advice
on how to manage the situation. It is important to check with
your pharmacist before taking other medications and to always
tell them about your nonprescription medicines or supplements.
---------------------------
The information in this newsletter was prepared and reviewed
by pharmacists for the Canadian Pharmaceutical Journal.
 |
Ask Your Pharmacist newsletter is produced through
an unconditional educational grant from APOTEX/PACE. |
 |
Back to Top | Click
for more Health Features
|
