Figures

Introduction

In general, there is a misconception among public that a larger strength drug equivalent to a stronger or better drug. Few examples that I encountered before include

• Ranitidine 150 mg should provide more gastric relief than pantoprazole 40 mg.
• Atorvastatin 20 mg is weaker than simvastatin 80 mg.
• Metformin 1000 mg will cause more drop in blood sugar than gliclazide MR 60 mg.
• Calcium lactate 1200 mg provides more elemental calcium than calcium carbonate 500 mg.

Yes, as a pharmacist, you know all the statements above are false. But, how would you explain to a layman?

NOTE: You may read here to revise on drug potency.

Elemental Calcium Content

Elemental calcium content in

Calcium acetate 667 mg tablet	169 mg elemental calcium (25%)
Calcium citrate 1500 mg tablet	315 mg elemental calcium (21%)
Calcium carbonate 500 mg tablet	200 mg elemental calcium (40%)
Calcium lactate 300 mg tablet	39 mg elemental calcium (13%)

NOTE:

• Calcium absorption from calcium acetate formulation is poor, hence it is used as phosphate binder, but not for calcium replacement.
• Calcium carbonate has acid-dependent absorption and should be taken with meals. Most people tolerate calcium carbonate well, but some people complain of mild constipation or feeling bloated.
• Calcium citrate are absorbed more easily than calcium carbonate. It has acid-independent absorption and can be taken with or without food.

Elemental Iron Content

Elemental iron content in

Ferrous fumarate	~33%
Ferrous sulphate	~20%
Ferric ammounium citrate	~18%
Ferrous gluconate	~12%

Commercial products

Zincofer capsule	115 mg elemental iron per capsule.
Iberet-Folic tablet	105 mg elemental iron per tablet.
Maltofer Fol chewable tablet	100 mg elemental iron per chewable tablet.
Ferrous fumarate 200 mg tablet	66.67 mg elemental iron per tablet.
Ferrocyte tablet	50 mg elemental iron per tablet.
Maltofer drops	50 mg elemental iron per 20 drops.
New Obimin capsule	30 mg elemental iron per capsule.
Obimin Pluz capsule	30 mg elemental iron per capsule.
Sangobion Complete capsule	30 mg elemental iron per capsule.
Maltofer syrup	10 mg elemental iron per ml.

Contents

Each g of	Contains
Magnesium sulphate (heptahydrate)	4.1 mmol of magnesium.
Potassium chloride	13.4 mmol of potassium and chloride.
Sodium bicarbonate	11.9 mmol of sodium and bicarbonate.
Sodium chloride	17.1 mmol of sodium and chloride.
Sodium phosphate (monobasic, anhydrous)	8.3 mmol of sodium and phosphate.
Sodium phosphate (monobasic, monohydrate)	7.2 mmol of sodium and phosphate.
Sodium phosphate (monobasic, dihydrate)	6.4 mmol of sodium and phosphate.

Calories

Each g of	Contains
Carbohydrate	4 kcal
Dextrose	3.4 kcal
Glycerol	4.3 kcal
Lipid	9 kcal
Protein	4 kcal

External Link

• Choosing a calcium supplement, 2020