# Calcium Citrate vs Calcium Carbonate

Discussion in 'Pharmacy Licensure and Exams' started by poda521, Aug 15, 2011.

1. ### poda521

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A patient takes 500mg of elemental Calcium daily from Calcium Citrate tablets. Pharmacy only has in stock Calcium Carbonate bottles which come as 1000mg of Calcium Carbonate per tablet. How many tablets of Calcium Carbonate must the patient take to get the same amount of calcium daily?

I understand that you have to go through the mEqs and mmols.
I'm supposed to calculate the MW of CaCO3 which equals 100mg.
Thus 100mg = 1 mmol of Ca in CaCO3.
And 100mg = 2 mEqs of Ca ions, 50mg = 1 mEqs.
So patient takes 10 mEqs of Calcium daily and there are 20 mEqs of Ca per tablet of CaCO3. So the answer should be that patient takes 1/2tab of Calcium Carbonate? Or must I always revert back to mEqs and mmols?

Another thing I wanted to bring up was, I remember reading that Iron had X% of Fe/tab in one formulation while another formulation had Y% of Fe/tab. Could I apply that method, finding the amount of elemental iron in each tablet and figuring out how many tabs to give?

2. ### metformin87 5+ Year Member

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im not sure what you're asking because i didnt read it all but calcium citrate is 21% calcium while calcium carbonate is 40% calcium

so if you got a question asking how much mg of calcium is in 1500mg of calcium citrate.... 0.21 x 1500 = 315mg of calcium then you cant turn that into meq or whatever the question wants from there

calcium citrate has better absorption but its a bigger tablet while calcium carbonate works best when taken with meals.. tums tuh tum tum tums

3. ### GoTeamVenture 5+ Year Member

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beginning and end = raddest post of the day

4. ### x3dgame 2+ Year Member

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You are making the question way to complicated. Just like what the other member said, 21% calcium in calcium citrate, and 40% in calcium carbonate.
The question already stated that the patient need 500mg of element calcium.
500mg / 0.4 = 1250 mg Calcium carbonate
So, the patient will need one and a quart tablet to get the same amount.

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