*According to FAA guidelines, non-sedating antihistamines may be used while flying after adequate individual experience has determined that the medication is well tolerated without significant side effects.
Now take a deep breath and feel the Allegra-D difference.
The ones you see in over-the-counter sleep aids are usually diphenhydramine and hydroxyzine.
(There are other types of antihistamines that affect H-2, H-3, and H-4 receptors.) People build up tolerance to them over time and when they stop taking them experience rebound insomnia.
According to Food and Drug Administration (FDA) estimates, over 60 million people receive prescriptions for tranquilizers every year.
As a group, tranquilizers act mostly on the brain by affecting the neurotransmitter gamma-aminobutyric acid (GABA).
Neurotransmitters are brain chemicals that facilitate communication between brain cells (neurons).
Although the various classes of CNS depressants work in different ways, ultimately it is through their ability to increase GABA activity (thereby decreasing brain activity) that they produce a drowsy or calming effect that is beneficial to those suffering from anxiety or sleep disorders.
For people who need to get to sleep, however, the drowsiness is the main benefit of antihistamines.However, these drugs are now more commonly—and more accurately—called neuroleptics or antipsychotics.Antihistamines make your sleepy by antagonizing central histimine-1 (H-1) receptors in the brain.Although a wide variety of substances can have tranquilizing effects, historically, the term "major tranquilizer" was applied to the category of drugs used to treat severe mental illnesses such as schizophrenia.This term, however, arose from the inaccurate belief that the major positive action of the earliest drugs used to treat this illness was sedating and that these drugs were on a continuum with other, less powerful, antianxiety drugs.