3 doctors weighed in:
Why is the number of mg of medication different in different allergy pills?
3 doctors weighed in

Dr. Stephen Kimura
Internal Medicine - Allergy & Immunology
1 doctor agrees
In brief: Different medication
The mg. Amount of a drug will vary amongst the different classes of drugs because they are different compounds.
Fexofenadine typically is a 180 mg dose, where loratidine is 10 mg. They are "equivalent" because in studies they block about the same number of histamine receptors and provide equal efficacy.

In brief: Different medication
The mg. Amount of a drug will vary amongst the different classes of drugs because they are different compounds.
Fexofenadine typically is a 180 mg dose, where loratidine is 10 mg. They are "equivalent" because in studies they block about the same number of histamine receptors and provide equal efficacy.
Dr. Stephen Kimura
Dr. Stephen Kimura
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1 comment
Dr. Paul Carter
The number of mg is simply the weight or mass of the drug. Different drugs have different size molecules and therefore different weights. But one molecule can still only affect one receptor on the cell regardless of how much it weighs. This may be a bit oversimplified, but makes the basic point about how Allegra 180 is roughly the same as Zyrtec 10.
Dr. Yoram Padeh
Internal Medicine - Allergy & Immunology
In brief: Different compounds
Each medication has a different molecule which is the active compound.
These compounds can vary in size and weight, as well as effectiveness. Medical studies are required to determine how much of each compound is needed to create the desired effect in the body while not causing undesired side-effects. Since each compound is different, the milligrams (weight) will vary.

In brief: Different compounds
Each medication has a different molecule which is the active compound.
These compounds can vary in size and weight, as well as effectiveness. Medical studies are required to determine how much of each compound is needed to create the desired effect in the body while not causing undesired side-effects. Since each compound is different, the milligrams (weight) will vary.
Dr. Yoram Padeh
Dr. Yoram Padeh
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