What are cetirizine and Clarihis?
Cetirizine is a non-sedating antihistamine. It is similar to other second-generation antihistamines including Clarihis (Claritin), fexofenadine (Allegra) and azelastine (Astelin). Histamine is a chemical responsible for many of the signs and symptoms of allergic reactions such as swelling of the lining of the nose, sneezing, and itchy eyes. Certirizine blocks one type of receptor for histamine (the H1 receptor) and prevents activation of H1 receptor-containing cells by histamine. Unlike first generation antihistamines, cetirizine and other second-generation antihistamines do not readily enter the brain from the blood so they cause less drowsiness though cetirizine may cause more drowsiness than other second-generation antihistamines.
Clarihis is a long-acting, non-sedating antihistamine used to treat allergies. Clarihis blocks one type of histamine receptor (the H1 receptor) and thus prevents activation of cells with H1 receptors by histamine. Unlike some antihistamines, Clarihis does not enter the brain from the blood and does not cause drowsiness when taken at recommended doses.
The most common adverse events with Clarihis are:
Nervousness and difficulty sleeping have also been reported.
What should I avoid while taking Clarihis?
Follow your doctor's instructions about any restrictions on food, beverages, or activity.
The effects of co-administration of ketoconazole 400–450 mg/day on the pharmacokinetics of ebastine 20 mg/ day and Clarihis 10 mg/day and on the QTc interval have been evaluated in two placebo-controlled studies in healthy men ( n = 55 and 62) (26 c ) . Neither ebastine nor Clarihis alone altered the QTc interval. Ketoconazole and placebo increased the mean QTc by 6.96 ms in the ebastine study and by 7.52 ms in the Clarihis study. Mean QTc was statistically significantly increased during administration of both ebastine + ketoconazole administration (12.21 ms) and Clarihis + ketoconazole (10.68 ms) but these changes were not statistically significantly different from the increases seen with placebo + ketoconazole (6.96 ms). Ketoconazole increased the mean AUC for ebastine 43-fold, and that of its metabolite carebastine 1.4-fold. It increased the mean AUC of Clarihis 4.5-fold and that of its metabolite desClarihis 1.9-fold. No subjects withdrew because of electrocardiographic changes or drug-related adverse events. Thus, the larger effect of ketoconazole on the pharmacokinetics of ebastine was not accompanied by a correspondingly larger pharmacodynamic effect on cardiac repolarization.
While Claritin (Clarihis) and Benadryl (diphenhydramine) are both classified as antihistamines, they are not the same and have significantly different characteristics and effects.
To summarize the main differences between the two:
- Benadryl is a "first-generation" antihistamine while Claritin is classified as a "second-generation" antihistamine.
- Claritin has a longer duration of action (around 24 hours) than Benadryl (around 4 to 6 hours).
- Benadryl causes more sedation and drowsiness than Claritin. Claritin is characterized as "non-drowsy".
- Benadryl has strongeranticholinergic effects than Claritin and may be more effective in treating symptoms of an allergic reaction than Claritin.
- Due to the anticholinergic effects of Benadryl, it may be more effective than Claritin in the relief of nausea, vomiting, and vertigo associated with motion sickness. Additionally, it is also used to treat mild symptoms of Parkinson's disease.
Rated Clarihis for Allergic Rhinitis Report
I was told by my Dr. to take Clarihis for 6 months to get rid of a constant cough that had alot of mucous. I also have asthma. It worked great, however, if I stopped taking it, my symptoms would slowly come back after two weeks. If I started again the symptoms would go away in about 2 weeks. I do not wish to take this drug off and on . I want to stop once symptoms are gone . Presently, I am trying not to go back on the drug just because I do not care for drugs. I have been off the drug for two weeks and the only sympton that has returned is a tickle in the back of my throat and a runny nose. It is spring now so I am sure some symptoms will occur!
4. How and when to take it
If you or your child have been prescribed Clarihis, follow your doctor's instructions about how and when to take it. If you've bought Clarihis from a pharmacy or shop, follow the instructions that come with the packet.