I don't know her or how she would react.

You might want to come to her with love and concern, and not mention the BP, or what you suspect. Maybe you could suggest going to the doctor with her because she is not acting like herself, and is acting quite out of character. Tell her it's not her fault, and you think she needs something else besides the antidepressants.

At the GP you can tell him that she had been on antidepressants alone, and has acted much differently, and explain the collateral damage, and what you have observed.

I believe he should get what you are trying to say without her going ballistic if she even agrees to go with you.

Hope it all works out for you. It's a very touchy situation.