Patricia, This question would be best asked of your physician who is familiar with you and your medical history. A pharmacist can also be helpful. But I can tell you that both medicines are antihistamines and work in similar ways to reduce allergy symptoms. Chlorpheniramine, though, is what is called a first-generation antihistamine, meaning it has been around longer.
It also has side effects that are unlikely with loratidine, namely drowsiness. I'm not sure it would be harmful to take both together, but I'm also not sure you would get any additional effect, since both basically do the same thing.
Hope that helps, but if not, call your doctor, OK?