What are alternative antihistamines to Zyrtec (cetirizine), Claritin (loratadine), and Allegra (fexofenadine)?

From the Guidelines

Alternative antihistamines to Zyrtec, Claritin, and Allegra include Xyzal (levocetirizine) and Clarinex (desloratadine), which are preferred over first-generation antihistamines due to their lower likelihood of adverse effects, such as sedation and anticholinergic effects, as stated in the study 1. When considering alternative antihistamines, it's essential to prioritize second-generation options, which have less or no tendency to cause sedation, performance impairment, and anticholinergic effects compared to first-generation antihistamines, as noted in the study 1. Some key points to consider when choosing an alternative antihistamine include:

• Xyzal (levocetirizine) is typically taken as a 5mg tablet once daily
• Clarinex (desloratadine) is usually prescribed as a 5mg tablet once daily
• First-generation antihistamines, such as Benadryl (diphenhydramine), cause significant drowsiness and are generally not recommended due to their potential for adverse effects, including sedation, performance impairment, and anticholinergic effects, as discussed in the study 1
• Second-generation antihistamines, like Xyzal and Clarinex, are designed to minimize sedation and other side effects, making them a better choice for most patients, as stated in the study 1
• Individual differences in metabolism and receptor sensitivity may affect how well a patient responds to a particular antihistamine, so switching to a different option may be necessary, and allowing 24 hours between medications can help prevent overlapping side effects, as noted in the example answer. In general, second-generation antihistamines, such as Xyzal and Clarinex, are preferred over first-generation antihistamines due to their improved safety profile and lower risk of adverse effects, as supported by the studies 1.

From the Research

Alternative Antihistamines

Some alternative antihistamines to Zyrtec (cetirizine), Claritin (loratadine), and Allegra (fexofenadine) include:

• Levocetirizine, which has been shown to have a favorable efficacy/safety profile and is effective in the treatment of allergic rhinitis and chronic idiopathic urticaria 2, 3
• Desloratadine, which is another second-generation antihistamine that has been compared to levocetirizine in several studies 2, 4
• Bilastine, olopatadine, azelastine, and rupatadine, which are also second-generation antihistamines that have been studied for their sedative effects compared to levocetirizine 4

Comparison of Antihistamines

Studies have compared the efficacy and sedative effects of different antihistamines, including:

• Levocetirizine vs. desloratadine: levocetirizine was more effective in improving pruritus in CIU patients 2
• Levocetirizine vs. diphenhydramine: levocetirizine did not significantly impair laboratory test performance, whereas diphenhydramine significantly affected divided attention and tracking after acute administration 5
• Levocetirizine vs. fexofenadine, loratadine, and other second-generation antihistamines: levocetirizine had modest sedative effects, but they were not different from other second-generation antihistamines 4

Other Options

Other antihistamines that may be considered as alternatives include:

• Cetirizine, which is the racemic mixture of levocetirizine and dextrocetirizine, and has been studied for its potential use in mitigating infusion-associated reactions and treating androgenetic alopecia 6
• Loratadine, which may be beneficial in the prophylaxis of G-CSF-related bone pain 6