Allergy medicines fall into a couple of groups: first-generation antihistamines, which are mostly available over the counter and include such common drugs as Benadryl and Chlor-tri-meton, and second-generation antihistamines, such as the following:
- Claritin (now available over the counter)
- Clarinex (similar to Claritin, but prescription)
- Zyrtec (prescription)
- Allegra (prescription)
Most people who have allergies take a second generation antihistamine. Not only are they more effective, they're less likely to cause sedation, which makes them a safer choice.
However, much of medicine is trial and error. No one treatment is right for every person. I know I've tried all of the second-generation medicines listed above. For me, Allegra works best to control my allergy symptoms, but I know others who swear by Zyrtec or Claritin.
Now, for the first time in several years, a new drug has been approved for use in treating allergies in the US: Xyzal. It's been in use for about six years in Europe and works much like Zyrtec, apparently. However, it is even less likely to cause sedation.
If you're not getting the symptom control you want from your antihistamine, you might want to talk with your doctor about whether Xyzal might be the right choice when it becomes available within the next few months.