I am a conservative medical provider, so I rarely, if ever, push the recommended dosages on Zyrtec or any drug. These things are carefully studied during the clinical trials so taking two may not be considered toxic or dangerous for a short period of time (even for a big guy), but this dose is not recommended. Like many drugs, this one is excreted by your kidneys, so why push the limit?
If this or any drug is not controlling allergy symptoms, it may be better to try something else. There are many ways to treat allergies than exceeding recommended dosages. Talk to your medical provider, but I bet he or she will not endorse your double dosage.
American Association of Clinical Endocrinologists, American Diabetes Association,
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Cetirizine (Zyrtec) is an antihistamine that is used for allergies. It is available over the counter. The maximum recommended dose of Zyrtec is 10mg per day. Studies have been done in people with chronic hives comparing the 10 mg to the 20 mg dose of Zyrtec and no advantage was seen with the higher dose. The recommended dose of Zyrtec is not based on weight and height.
Whenever you take a higher than recommended dose of a medication you increase your risk of side effects. Although Zyrtec is available over the counter that doesn’t mean it is harmless. Zyrtec can cause sleepiness and this effect is increased when Zyrtec is combined with alcohol or other drugs that cause sedation. Zyrtec use has also been associated with liver damage in rare individuals.
Play it safe and stick with the recommended dose. Talk with your doctor about using Zyrtec and whether the benefits of increasing the dose outweigh the risks.
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