| First generation antihistamines | Second generation antihistamines |
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| | Cetirizine (Zyrtec, Allecet, Texa, Zetop) |
| | Loratadine (Clarityne, Allergex-non drowsy, AP Loratidine, Pollentyme); |
Active ingredient and examples of trade names --> | Chlorpheniramine (Allerhist®, Allergex®) | Desloratadine (Deselex, Dazit, Adco-Desloratidine, Clarex 5, Neolori; |
| Promethazine (Daralix®, Prohist®, Lenazine®, Phenergan®) | Fexofenadine (Telfast, Fexo, Fastway, Tellerge); |
| | Levocetirizine (Xyzal, Allerway 5, Cetizal 5); |
| | Rupatadine (Rupanse); |
| | Levocabastine (Sinumax allergy nasal spray); |
| | Azelastine nasal spray (Rhinolast) |
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Researched in children | Less extensively researched | Extensively researched |
Sedative | Very Sedative | Less sedative or not sedative |
Duration of action | Short acting (need to be taken frequently: three to four times per day) | Long acting (can be taken once daily) |
Dry mouth and constipation | Common occurrence | Less common |
Hyperactivity, insomnia, convulsions, reduction in “deep” sleep | Potential exists | Less likely to occur |
Increased appetite | Potential exists | Less likely to occur |
Serious side effects when taken with other drugs (e.g. antifungals, erythromycin and azithromycin antibiotics) | Common | Unlikely to occur |
Poor concentration and work or school, impaired learning | Commonly described | Less likely to occur |
Lethal in overdose | Has been described in infants and young children | No fatalities described |
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