What is the use of Chlorpheniramine (antihistamine) intravenous (IV) administration in pediatric patients?

From the Guidelines

Intravenous chlorpheniramine should only be used in pediatric patients in specific emergency situations, such as severe allergic reactions, and with careful monitoring due to the risk of adverse effects, as recommended by the most recent guidelines 1. The typical IV dose for children can be determined based on age, with dosages ranging from 250 µg/kg for children under 6 months to 10 mg for children over 12 years, as outlined in a study from 2009 1. However, it's crucial to prioritize the use of epinephrine as the first-line treatment for anaphylaxis, as emphasized in a 2020 practice parameter update 1. When administering IV chlorpheniramine, it's essential to be aware of the potential side effects, including hypotension, dizziness, and sedation, and to use caution in children with pre-existing medical conditions, such as cardiac conditions, seizure disorders, or respiratory problems. Key considerations for the use of IV chlorpheniramine in pediatrics include:

• The medication's onset of action is rapid, but the risk of adverse effects is higher compared to other administration routes
• The use of antihistamines, including chlorpheniramine, should not delay the administration of epinephrine in cases of anaphylaxis, as highlighted in guidelines from 2010 1
• Careful monitoring is necessary when administering IV chlorpheniramine to pediatric patients, especially in emergency situations.

From the Research

Chlorpheneramine Intravenous Use in Pediatrics

• The use of chlorpheniramine in pediatrics is a topic of interest, with several studies investigating its pharmacokinetics, efficacy, and safety in children 2, 3, 4, 5, 6.
• A study published in 1982 found that chlorpheniramine has a mean serum half-life of 13.1 hours, a mean volume of distribution of 7.0 L/kg, and a mean clearance rate of 7.2 ml/min/kg in children with allergic rhinitis 2.
• Another study published in 2016 found that chlorpheniramine was the most common antihistamine prescribed off-label in pediatric patients, with 55.5% of prescriptions being off-label 3.
• A 2023 study found that antihistamines, including chlorpheniramine, may have a beneficial effect in the management of anaphylaxis, with patients treated with prehospital antihistamines being less likely to have uncontrolled reactions and be admitted to the hospital 4.
• However, a 2019 study reported two cases of chlorpheniramine-induced anaphylaxis, highlighting the potential risks associated with its use 5.
• A 2024 review of the literature found that chlorpheniramine has a wide range of potential clinical applications, including the treatment of allergic conditions, asthma, and depression, and that its use may be explored for other clinical indications such as COVID-19 6.

Pharmacokinetics and Efficacy

• The pharmacokinetics of chlorpheniramine in children have been studied, with findings suggesting that it has a large volume of distribution and a relatively long half-life 2.
• The efficacy of chlorpheniramine in treating allergic rhinitis and other conditions has been demonstrated in several studies 2, 4, 6.

Safety and Risks

• The safety of chlorpheniramine in pediatric patients has been a concern, with reports of off-label prescribing and potential risks such as anaphylaxis 3, 5.
• However, the majority of studies suggest that chlorpheniramine is generally well-tolerated and effective in treating allergic conditions in children 2, 4, 6.