Can You Take More Than 180mg Of Allegra (Fexofenadine) Per Day?

Answer

Even though the FDA (Food and Drug Administration) has approved Allegra (fexofenadine) at a maximum daily dose of 180mg per day, several studies have shown that higher dosages can be safe, and effective for some individuals treating certain conditions.

Now, you stated that your doctor prescribed you Allegra at a higher than usual dose (i.e., greater than 180gm per day) to help with a severe reaction you were having, and as mentioned, studies show that high doses can be helpful for some (studies specifically show high doses can be helpful for hives and itching).

However, I wouldn't recommend staying on doses over 180mg unless specifically recommended by your doctor. Although studies exist evaluating doses over 180mg per day, there is still a lack of long-term safety data with these high doses.

Your doctor, knowing your medical situation, will be able to discuss the potential risks and benefits of continuing therapy at this dose (fexofenadine 180mg twice daily). So, in other words, only continue on this current high dose if it is recommended by your doctor and you can are appropriately monitored.

I will say the preliminary studies are promising. I discuss this more in the next section but studies have shown short-term dosing up to 800mg has been generally well-tolerated.

What Do The Studies Say?

One study, which tested the safety and effectiveness of the drug using higher than usual doses (up to 800mg per day) for urticaria (hives) found it effective and well-tolerated, with only minimal side effects reported. The study concluded:

We found fexofenadine in higher doses effectively controlled urticaria in majority of the patients. Side effects were noted in the form of headache and sedation.

Another study, which evaluated doses up to 360mg per day (the dose you are taking), found that it was both safe and effective. The study specifically noted that these high doses did not cause any negative CNS (central nervous system) effects, like some antihistamines can do (e.g. sedation, dizziness, etc). This study concluded:

Fexofenadine at a dose of 360mg is demonstrably free from disruptive effects on aspects of psychomotor and cognitive function in a study where the psychometric assessments have been shown to be sensitive to impairment...

These studies have also not noted any issues with high-dose Allegra causing any cardiac problems, which has been reported with some antihistamines used at high doses.

Overall, there does seem to be some positive evidence of benefit in using higher than FDA-approved doses of fexofenadine, but more studies are needed to determine the long-term safety of such doses. Regardless, preliminary evidence shows that it can be safe and effective.

Final Words

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