How do painkillers cure headaches?

We all feel pain differently, depending on the severity of the
injury or ache, as well as our health and our pain threshold.
When you are in pain, nerve endings transmit the pain
signal to the brain via the spinal cord. The brain then interprets the
level of pain.
There are two key types of painkillers that are commonly used.
The first include ibuprofen and paracetamol, which block the body’s
‘prostaglandins’ (chemicals that produce swelling and pain) at the
source of the pain, reducing swelling in the area and reducing the
intensity of pain. These ‘aspirin medicines’ are used frequently for
mild to moderate pain, but they can only work up to a certain intensity
of pain. There are different types of painkillers within this group, such
as anti-inflammatory medicines, like ibuprofen, which are commonly
used to treat arthritis, sprains and strains. Aspirin is used to help lower
the risk of blood clots when used in a low dosage, as they thin the
blood. Paracetamol is what’s known as an analgesic, which is used for
reducing pain and lowering a temperature.
The second type of
painkillers include morphine
and codeine (narcotic
medicines), which block
the pain messages in the
spinal cord and the brain.
This is for much more
severe pain. As both types
of painkillers use slightly
different methods to treat
pain, they can be
combined, such as in
co-codamol, which blends
codeine and paracetamol.