Take this medication by mouth on an empty stomach (at least 1 hour before or 2 hours after a meal). Take this medication with water. Do not take with fruit juices (such as apple, grapefruit, or orange) since they may decrease the absorption of this drug.

Antihistamines work by blocking a substance called histamine in your body. Histamine is known for causing allergy symptoms. Blocking it helps prevent symptoms of seasonal allergies or hay fever. Both Allegra and Zyrtec are effective at treating allergy symptoms and take a similar amount of time to start working.

Allegra generally starts working about 1 hour after you take it. The effects of a 60 mg dose last about 12 hours, and a 120 mg or 180 mg dose last about 24 hours.

The plain Allegra is also available in 24 and 12 hour doses, but the 24 hour dose actually contains three-times more medicine than the 12 hour dose (180 mg vs. 60 mg). Allegra is almost as strong as Zyrtec, but far less sedating. Claritin is the least effective of the three.

Newer antihistamines like Allegra and Claritin are generally safe for daily use. But allergy medications with decongestants, such as Claritin-D or Benadryl-D, could make your allergies worse with long-term use.

The chances of experiencing drowsiness with Allegra are very low. In fact, it's one of the antihistamines that's least likely to make you feel sleepy. But drowsiness with Allegra is still possible. The risk of drowsiness is higher if you also take other medications that make you tired, or if you drink alcohol.

Newer antihistamines like Allegra and Claritin are generally safe for daily use. But allergy medications with decongestants, such as Claritin-D or Benadryl-D, could make your allergies worse with long-term use.

The chances of experiencing drowsiness with Allegra are very low. In fact, it's one of the antihistamines that's least likely to make you feel sleepy. But drowsiness with Allegra is still possible. The risk of drowsiness is higher if you also take other medications that make you tired, or if you drink alcohol.

Yes, you can take fexofenadine (Allegra) only when you need it if you have allergy symptoms once in a while. But if you have allergy symptoms on a daily basis, taking it regularly is more likely to give you the most relief from your allergies. Can I take fexofenadine (Allegra) if I'm pregnant?

Directions. Adults and children 12 years of age and over: Take one 180 mg tablet with water once a day; do not take more than 1 tablet in 24 hours. Children under 12 years of age: do not use.

Directions. Adults and children 12 years of age and over: Take one 180 mg tablet with water once a day; do not take more than 1 tablet in 24 hours. Children under 12 years of age: do not use.

Yes, you can take fexofenadine (Allegra) only when you need it if you have allergy symptoms once in a while. But if you have allergy symptoms on a daily basis, taking it regularly is more likely to give you the most relief from your allergies.