SF: man taking a drug and entering the thoughts of the woman *possible spoiler*

[Bogdan]

I read this book at least 10 years ago. It was probably science fiction, and in the book a man was taking a drug and entering the thoughts of a woman (his girlfriend?). I know there was some sense of urgency (*maybe* government troops approaching) and he was exploring together with her, he in her thoughts, she in his. And in the end he takes an overdose and rises higher understanding the world.
I know it's a bit vague but it's all I have.

[Lobstergirl, au gratin]

Bogdan, are you still looking for this or did you find it?