2 doctors weighed in:

How many milligrams of antihistamine can a person take at one time?

2 doctors weighed in
Dr. Thomas Shen
Internal Medicine - Allergy & Immunology
1 doctor agrees

In brief: Unclear

Different antihistamines have different potencies.
10 mg of Zyrtec is equivalent to 180mg of Allegra (fexofenadine). Mg doseage as in all medicines are drug specific. In regard to toxic levels, each has it's own known limit. However too much antihistamine can lead to deadly arrythmias/ Please use the recommended dose.

In brief: Unclear

Different antihistamines have different potencies.
10 mg of Zyrtec is equivalent to 180mg of Allegra (fexofenadine). Mg doseage as in all medicines are drug specific. In regard to toxic levels, each has it's own known limit. However too much antihistamine can lead to deadly arrythmias/ Please use the recommended dose.
Dr. Thomas Shen
Dr. Thomas Shen
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