What are the differences between chlorpheniramine maleate and dexchlorpheniramine maleate?

Closely related. Both medications are potent antihistamines. Both have similar side effects, mainly sedation and anti-cholinergic (dry mouth, larger pupils, may cause constipation and in older men, difficulty in urination. Dexchlorpheniramine requires a prescription. Its chemical structure is only minimally different from chlorpheniramine.