Chlorpheniramine, usually produced as chlorpheniramine maleate, is a first generation antihistamine in the same family as diphenhydramine HCl. Unlike diphenhydramine HCl, it is not likely to produce severe drowsiness in users, although drowsiness is one of the possible side-effects of chlorpheniramine. While the most common uses for chlorpheniramine are to treat allergy symptoms including itching, runny nose, and itchy or burning eyes, the medication has been studied for its possible anti-depressant effects. When attempting to determine an appropriate chlorpheniramine dosage, the most important factors to consider are the age of the patient, the condition, prior experience with the drug, individual product recommendations, and the use of other medications.
When administering immediate-release medications, the base chlorpheniramine dose for adults is 4 mg every four to six hours, while extended-release products should contain 8 to 12 mg. Daily use should not exceed 24 mg. The dose for children is 0.16 mg per pound of the child's weight per day, broken into doses administered every four to six hours. On average, this means that children between two and six years old will generally use 1 mg every four to six hours up to a maximum of 6 mg daily, while a child between six and 12 years old will generally use 2 mg every four to six hours up to a maximum of 12 mg daily. Children over the age of 12 should follow the chlorpheniramine dose recommendations for adults.
While the potency of some medications is affected by food consumption, chlorpheniramine is unaffected by whether it is taken with food. There is considerable variability within the general population in the dosage required for the medication to be effective, with some patients requiring far lower doses than others. When administering chlorpheniramine for the first time, the lowest recommended dose should be used first. If a low dose does not produce adequte symptom relief, a higher dose can then be taken. Particular caution should be used with older adults, as sensitivity among adults to the drug has been found to increase with age.
It is advisable to err on the side of caution when determining how large a chlorpheniramine dose to use, as the side effects increase dramatically when the dose increases. The risk is higher in children, who may suffer from much more serious side-effects than adults, including hallucinations, convulsions or even death. Patients with impaired liver function may metabolize the drug at a slower rate, resulting in a much lower chlorpheniramine dose requirement.
