Steve,

Huge disclaimer on this since I'm not a doctor, but I was under the impression that chemical changes from the initial concussion resolve in about 3 weeks and that initial window is when there is real concern about what drugs you are taking and such.

After that, it would just be PCS symptoms that would linger, so the calculation would just be whether the drug had a side effect that exacerbated your specific set of PCS symptoms?

My gut is that you are overthinking these medication concerns. You shouldn't be causing your brain any "damage". Check the side effects and make sure they aren't going to stack with what you've already got going, check with your doctor, then take the drug if it's being recommended. If it doesn't go well, come off it, and things will probably right themselves.

Many people with lingering PCS symptoms end up taking medication for headache and such. Some people take a medication for anxiety. All of this is fine to take. It's just about making your symptoms better and not worse.

Best of luck!