Chlorpheniramine is one of the more dangerous drugs found OTC. It has the nasty effect of causing optic nerve damage with use and is fairly toxic. It also provides VERY little sedation. This is the drug in the coricedin cough and cold DXM pills that limited the number you could take safely.
It is by no means safe to take and should be avoided like a scurvy rabbit on a mating spree. Go to the store and get Diphenhydrinate/Diphenhydramine, or Doxylamine. All 3 are safe and have substantial sedation, though doxilamine is stronger and may be the only one capable of puting you to sleep now. The first 2 mentioned are the same chemical for all purposes.
Diphenhydrinate is the 8-chlorotheophyllinate salt of diphenhydramine. Basically this just means that dosage of one is different from the other, but they are in single doses in pills at the store so MG doesnt matter much here.