From the Guidelines
Taking two different types of antihistamines simultaneously is not recommended without medical supervision due to potential increased risk of adverse effects. When considering the use of antihistamines, it's essential to understand the differences between first-generation and second-generation antihistamines, as highlighted in the study by 1. First-generation antihistamines have significant potential to cause sedation, performance impairment, and anticholinergic effects, making second-generation antihistamines generally preferred for the treatment of allergic rhinitis. Some key points to consider when using antihistamines include:
- Second-generation antihistamines, such as fexofenadine, loratadine, and desloratadine, do not cause sedation at recommended doses, as noted in the study by 1.
- Combining antihistamines can increase the risk of excessive drowsiness, dry mouth, blurred vision, urinary retention, and increased risk of overdose.
- In some cases, a healthcare provider might recommend combining an oral antihistamine with a nasal antihistamine spray or eye drops for targeted symptom relief, but this should only be done under medical guidance.
- If you're not getting adequate relief from your current antihistamine, it's best to consult your doctor about adjusting your dose, trying a different antihistamine, or adding other types of allergy medications rather than combining antihistamines on your own, as suggested by the study by 1.
From the Research
Safety of Using Two Types of Antihistamines
- There is no direct evidence in the provided studies that addresses the safety of using two types of antihistamines simultaneously 2, 3, 4, 5.
- However, the studies suggest that antihistamines can be used in combination with other medications, such as intranasal corticosteroids, to treat allergic rhinitis 3, 4.
- The guidelines for using antihistamines recommend substituting one antihistamine with another from a different class if the first one is not effective 2.
- Second-generation oral antihistamines and intranasal corticosteroids are considered the mainstays of treatment for allergic rhinitis, and combination therapy may be effective for some patients 3, 4.
- The choice of antihistamine and treatment approach should be based on the individual patient's symptoms, severity, and preferences 3, 4, 5.