Description: Histamine H1 Receptor Antagonist; Second Generation; Piperazine Derivative
CSA NA – FDA Approved – REMS (N) – Can Ship
How Does It Work
Cetirizine/Reactine/Zyrtec inhibits the H1 histamine receptors on effector cells in the respiratory tract, blood vessels, and gastrointestinal tract.
Indications For Use
Cetirizine/Reactine/Zyrtec is officially indicated for allergic rhinitis, allergic conjunctivitis, and chronic spontaneous urticaria (hives). It is commonly prescribed off-label as an adjunct to epinephrine in anaphylaxis, angioedema, as an adjunct for infusion reactions, and acute urticaria (May also be used for conditions not listed)
Before starting Cetirizine/Reactine/Zyrtec make sure your physician is aware of any allergies or medications you currently take, if you have liver disease, kidney disease, or are pregnant or breastfeeding.
5-20mg once or twice daily depending on the indication, the severity of symptoms, and patient response
Pharmacist Tips On Using
How to Take: Follow instructions provided by physician/pharmacy label, take consistently at same times each day unless otherwise directed, store at room temperature.
You Need to Avoid: Do not operate heavy machinery, or mix with alcohol if this medication causes sedation
Side effects are uncommon with this medication however some that may occur are drowsiness or headache.
Note this is not a complete list of side effects, only common ones.
Frequently Asked Questions
This medication is supposed to be non drowsy, why does it make me so tired?
Blocking histamine receptors in the frontal lobe is what causes sedation from antihistamines. First generation antihistamines like diphenhydramine (Benadryl) were prone to crossing the blood brain barrier and causing sedation with second generations being less likely. Some people due to genetic and other factors are more prone to allowing cetirizine to pass into the brain and this causes sedation. If this occurs, try loratadine (Claritin) or another second-generation antihistamine as cetirizine is the most likely of them to have this issue.