• Soluble painkillers

Effervescent painkillers are high in salt, containing up to 1g per tablet.

Too much salt can raise your blood pressure, which puts you at increased risk of health problems like heart disease and stroke.

You may want to consider switching to a non-effervescent painkiller, especially if you have been advised to watch or reduce your salt intake.

• Ibuprofen

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, diclofenac and naproxen, seem to work better when there's clear evidence of an inflammatory cause, such as arthritis or an injury.

They should not be used for long periods unless you have discussed it with your doctor.

If you take them for long periods, there's an increased risk of stomach upset, including bleeding, and kidney and heart problems.

Do not take more than the recommended dose, as this will increase the risk of serious side effects.

Pregnant women should not take ibuprofen unless a doctor recommends and prescribes it. Paracetamol is the recommended alternative in pregnancy.

• Morphine

Morphine and morphine-like drugs (such as oxycodone, fentanyl and buprenorphine) are the strongest painkillers there are.

Depending on your individual circumstances, these types of painkiller may be prescribed as a patch, an injection, or sometimes in a pump you control yourself.

But they all work in similar ways and should only be used for severe pain.

They'll only be prescribed after consultation with a doctor or a pain specialist. The dose and your response will be closely monitored.

These drugs should only be used as part of a long-term plan to manage your pain.