If you have pain, take a painkiller.
Please give me a painkiller.
I need a painkiller.
She took some painkillers for her headache.
Take some painkillers and go to bed.
After the operation you will need to take painkillers for a few days.
You should take some painkillers for your headache.
This is a strong painkiller and you've already taken 2.
Good painkiller is better than regular booze.
I'm out of painkiller. I've gotta get some.
These painkillers are only available on prescription.