Kick in

'As the anaethetic kicked in, XYZ could feel herself drifting off into the world of sleep.'

I'd use 'kick in' to refer to a substance that is beginning to have an effect, and not for pain, which is the effect in itself.

'As the snake's venom kicked in, I felt a searing pain in my chest.'

Thank you.
So there's nothing violent in the idea?

'Kicked in' does give the sense of a certain amount of violence - metaphorically speaking - such as the idea that a drug has a sudden effect.

Thanks again, Mr matthewq

"Kick in" has nothing to do with the verb "to kick" (i.e. a swift upward movement of the foot) therefore contains no hints of violence, unlike "kick open", "kick down", "kick off", "kick one's ****", or "kick up one's heels", etc.

Thanks, hbae!

Yes, you're right, there's no connection with violence in the physical sense, as there is when someone would say, 'I'm going to kick your face in.' But I do think that the phrase does convey the idea of violence in the sense of 'a powerful and sudden force.' I wouldn't seriously say, 'The cough medicine is kicking in,' unless I wanted to be called a wimp. The effect of cough medicine, in this cas

a powerful strength you can do nothing against?

I suppose so, unless you counter a drug with an antidote, or use a drug which has an opposite effect.

and then the antidote kicks in...
Thank you, Mq!