From the Guidelines
Chlorpheniramine should not be used as a first-line treatment for allergic rhinitis due to its potential to cause sedation, performance impairment, and anticholinergic effects, and instead, second-generation antihistamines or other alternative treatments should be considered. Chlorpheniramine is a first-generation antihistamine medication used to treat allergy symptoms such as sneezing, itching, watery eyes, and runny nose. The standard adult dosage is 4 mg every 4-6 hours, not exceeding 24 mg in 24 hours, while children's dosages vary by age and weight 1. Chlorpheniramine works by blocking histamine receptors, preventing the chemical from causing allergy symptoms. As a first-generation antihistamine, it commonly causes drowsiness and should not be taken when driving or operating machinery. Other side effects may include dry mouth, blurred vision, and urinary retention. It should be used with caution in patients with glaucoma, enlarged prostate, or certain heart conditions. According to the study published in the Journal of Allergy and Clinical Immunology 1, first-generation antihistamines have significant potential to cause sedation, performance impairment, and anticholinergic effects, and second-generation antihistamines are generally preferred over first-generation antihistamines for the treatment of allergic rhinitis.
Key Points to Consider
- Chlorpheniramine is associated with sedative effects, including drowsiness and performance impairment, which can be dangerous, especially when driving or operating machinery 1.
- The medication can also cause anticholinergic effects, such as dry mouth, constipation, and urinary retention, which can be undesirable and potentially dangerous 1.
- Second-generation antihistamines are generally preferred over first-generation antihistamines, such as chlorpheniramine, due to their lower risk of sedation and anticholinergic effects 1.
- Chlorpheniramine should be used with caution in older adults, who are more sensitive to its psychomotor impairment and are at increased risk for complications such as fractures and subdural hematomas caused by falls 1.
- Patients should inform their healthcare provider about all other medications they're taking to avoid potential interactions, and avoid alcohol while taking this medication as it can increase drowsiness.
Alternative Treatments
- Second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, which have a lower risk of sedation and anticholinergic effects 1.
- Intranasal corticosteroids, which are typically the most effective medication class for controlling sneezing, itching, rhinorrhea, and nasal congestion, the 4 major symptoms of allergic rhinitis 1.
- Oral anti-LT agents, alone or in combination with antihistamines, which have proven to be useful in the treatment of allergic rhinitis 1.
From the FDA Drug Label
Uses temporarily relieves these symptoms of hay fever or other upper respiratory allergies: runny nose sneezing itchy nose or throat itchy, watery eyes The main use of Chlorpheniramine is to temporarily relieve symptoms of:
- Hay fever
- Upper respiratory allergies, including:
- Runny nose
- Sneezing
- Itchy nose or throat
- Itchy, watery eyes 2
From the Research
Overview of Chlorpheniramine
- Chlorpheniramine is a first-generation H1 antihistamine that has been used since the 1950s 3
- It is commonly used to treat allergic conditions, such as allergic rhinitis, and is available over-the-counter for cough and colds 4, 3
Clinical Applications
- Chlorpheniramine has been explored for its potential use in treating various conditions, including asthma, plasma cell gingivitis, chronic urticaria, and depression 3
- It has also been studied for its antiviral properties against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 3
- In the management of anaphylaxis, antihistamines like chlorpheniramine may have a beneficial effect, although epinephrine is the first-line treatment 5
Comparison with Other Antihistamines
- Chlorpheniramine is associated with adverse events, such as sedation and impairment, especially at higher doses 4
- Newer-generation antihistamines, such as desloratadine, cetirizine, and fexofenadine, have been developed to minimize adverse events 4
- In a study comparing different antihistamines, chlorpheniramine was found to have a higher frequency of significant side effects compared to trimeprazine, but was preferred by patients over other antihistamines like tripelennamine and hydroxyzine 6
Role in Allergic Rhinitis Management
- Chlorpheniramine is one of the options for managing allergic rhinitis, although second-generation oral antihistamines and intranasal corticosteroids are generally recommended as first-line treatments 7
- The management of allergic rhinitis should be patient-specific, taking into account the type, duration, and severity of symptoms, comorbidities, prior treatment, and patient preference 7