What is the differential medication between chlorpheniramine (Chlorpheniramine) maleate and loratadine (Loratadine)?

From the Guidelines

Loratadine is generally preferred over chlorpheniramine maleate for the treatment of allergic rhinitis due to its minimal sedation and fewer central nervous system effects, as supported by the most recent evidence 1. Chlorpheniramine maleate and loratadine are both antihistamines used to treat allergy symptoms, but they differ significantly in their properties and usage.

• Chlorpheniramine is a first-generation antihistamine that effectively relieves allergy symptoms but commonly causes drowsiness, dry mouth, and blurred vision.
• It typically requires dosing every 4-6 hours (4-8mg per dose, not exceeding 24mg daily for adults).
• Loratadine, a second-generation antihistamine, provides 24-hour relief with minimal sedation at the standard adult dose of 10mg once daily.
• Loratadine is generally preferred for daytime use and long-term management because it doesn't cross the blood-brain barrier significantly, resulting in fewer central nervous system effects, as noted in the study 1. The key difference lies in their chemical structures - chlorpheniramine's ability to cross into the brain causes its sedating effects, while loratadine's modified structure prevents this, making it more suitable for daily use without impacting alertness or cognitive function.
• According to the study 1, second-generation antihistamines like loratadine are preferred over first-generation antihistamines like chlorpheniramine due to their lower risk of adverse effects.
• The study 1 also highlights that second-generation antihistamines have less or no tendency to cause sedation, performance impairment, and anticholinergic effects, making loratadine a better choice for patients who require long-term management of allergic rhinitis.

From the FDA Drug Label

Active ingredient (in each tablet) Chlorpheniramine maleate 4 mg ACTIVE INGREDIENT(S) (in each 5 mL teaspoonful) Loratadine USP, 5mg The main difference between chlorpheniramine maleate and loratadine is:

• Active ingredient: Chlorpheniramine maleate vs Loratadine
• Dosage form: Tablet vs Liquid (5 mL teaspoonful)
• Dose: 4 mg vs 5 mg 2 3

From the Research

Differential Medication: Chlorpheniramine Maleate vs Loratadine

• Chlorpheniramine maleate and loratadine are both antihistamines used to treat allergic reactions, but they have different properties and effects.
• Loratadine is a long-acting antihistamine agent, exhibiting partial selectivity for peripheral histamine H1-receptors 4.
• Chlorpheniramine, on the other hand, is a first-generation antihistamine that can cause more sedation and central nervous system effects compared to loratadine 4, 5.
• In terms of efficacy, loratadine has been shown to be as effective as chlorpheniramine in treating allergic rhinitis and chronic urticaria, but with fewer sedating effects 4.
• Loratadine has a faster onset of action and a longer duration of action compared to some other antihistamines, including chlorpheniramine 5.
• The choice between chlorpheniramine maleate and loratadine may depend on the specific needs and preferences of the patient, as well as the severity of their allergic symptoms.

Comparison of Side Effects

• Loratadine is generally well-tolerated, with common adverse events including somnolence, fatigue, and headache 4.
• Chlorpheniramine, on the other hand, can cause more sedation and central nervous system effects, including somnolence, drowsiness, and impaired cognitive function 6.
• Loratadine has been shown to have a lower incidence of sedation and central nervous system effects compared to chlorpheniramine 4, 5.

Clinical Studies

• Several clinical studies have compared the efficacy and safety of loratadine with other antihistamines, including chlorpheniramine 4, 5, 6.
• These studies have generally shown that loratadine is as effective as other antihistamines in treating allergic rhinitis and chronic urticaria, but with fewer sedating effects.
• One study found that brompheniramine, a first-generation antihistamine, was more effective than loratadine in treating allergic rhinitis, but caused more sedation and central nervous system effects 6.