What is the proper four-hour dose for an adult or child over the age of 12 to take Chlor-Trimeton?

Please do not adjust your dosage unless the doc/pharmacist specifically instructs you to do so.

Oral Chlorpheniramine Dosage for Adults
Depending on the particular product, a typical chlorpheniramine dose for adults is 4 mg every 4 to 6 hours (not to exceed 24 mg per day) for immediate-release products or 8 to 12 mg every 8 to 12 hours (not to exceed 24 mg in 24 hours) for various extended-release products. Keep in mind that these are general guidelines and specific medications may have different directions. Be sure to follow the directions for your particular product.

Older adults, who may be more sensitive to chlorpheniramine side effects, may need a lower or less frequent dosage.

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In general, chlorpheniramine can be dosed by age or by weight for children. Based on weight, a standard recommended dose is 0.35 mg per kg per day (0.16 mg per pound per day), divided into smaller doses given every four to six hours. Based on age, the recommended chlorpheniramine dose is as follows:

* Age 2 to 6 -- 1 mg every 4 to 6 hours, not to exceed 6 mg in 24 hours
* Age 6 to 12 -- 2 mg every 4 to 6 hours, not to exceed 12 mg in 24 hours
* Age 12 and older -- usual adult dosing.

It should be noted that medications (including chlorpheniramine) should not be used to treat the common cold in children under four years old, as cold medications have not been shown to be effective or safe in this age group.

However, please seek more professional info from the doc/pharmacist who prescribed the med, hope to have answered your question to satisfaction?