First off -wow! Thank you for all the comments/questions in response to Catie’s Orange Juice and Allegra article. Her article was about the Zyrtec commercial about not being able to drink juice and take Allegra at the same time. Since she posted that article, we have received great questions/comments that we want to follow up on.
I LOVE juice -what do I do? Take the Allegra at night! It is actually best to take the daily antihistamines (Allegra, Zyrtec, Claritin) at night. This is because it is best to take the antihistamine 2-5 hours before being exposed to allergens. And guess when pollen levels are at their worse? Usually between 5-10 AM! So, if Allegra is taken at night, you wake up ready to fight off allergens and free to drink as much juice as you want!
Does it hurt me to drink juice and take Allegra at the same time? No, nothing bad will happen to you if you drink juice and take Allegra at the same time. However, drinking juice and taking Allegra at same time can actually decrease the amount of Allegra that is absorbed (up to 50% in one study) -this means the Allegra doesn’t work as well.
What about orange juice, cranberry juice, grapefruit juice, grape juice….? Most of the stuidies have been with grapefruit juice, however what causes the interaction is in all fruit juices -so no juice is “safe”.
How long must I separate drinking juice and taking Allegra? It is best to separate drinking juice and taking Allegra by at least 4 hours. It is time dependent -so, if you take it together up to 50% won’t be absorbed, if you wait 2 hours 25% won’t be absorbed, if you wait 4 hours mostly all of it will be absorbed.
Can I just take twice the prescribed dose in order to overcome the loss caused by the orange juice? Not a great choice for a couple of reasons. First, because it is not an exact science of how much Allegra is absorbed so most likely too much Allegra will get into the body. This increases the risk of side effects. And because doubling the dose is not very cost effective!
Is it the vitamin C in the juice that causes the interaction? No it is not the vitamin C that causes the interaction. It is most likely caused by fruit juices inhibiting an organic anion transporting peptide (OATP1A2). By inhibiting OATP1A2, the absorption of Allegra is reduced.
Why would Zyrtec advertise for Allegra? I really don’t know…
Which is better -Zyrtec, Allegra or Claritin? All three -Zyrtec (cetirizine), Claritin (loratadine) and Allegra (fexofenadine) are now available OTC and all work well. Studies show that Zyrtec and Claritin are more likely to cause drowsiness then Allegra. I must admit I am slightly biased because I heart me some Allegra but others claim Zyrtec or Claritin works better for them. I would think about cost and what works best with the least side effects for you personally.
If you decide OTC Allegra is for you -go visit their website and get a coupon!
I hope this clears some questions up! Thank you for all your comments and questions -please keep them coming!