Understanding pain medicine

painkillers and drugs and how they work for your arthritis

Arthritis pain is often the starting point for seeking treatment, even before your diagnosiss. Understanding pain medicines, pain killers and drugs and how they work for your arthritis is a good start in managing pain.

To understand how pain relief works, we must first talk about how our body experiences pain. Nerve endings in most body tissues, respond to damage. When there is damage in your body (arthritic finger, burnt hand), pain-producing chemicals are released in your body to start the pain messages. The nerve fibres only create a nerve pain message if there are enough pain-producing chemicals.

The messages started by these chemicals are transmitted along the nerves to the spinal cord.  This is just like electricity travelling along power lines. The first pain-transmitting nerves end at the spinal cord. More substances are released there, and different nerves continue the pain message until it reaches your brain. Your brain tells you that you are in pain.

The two most common types of drugs for pain are paracetamol and non-steroidal anti-inflammatories (NSAIDs) like ibuprofen or diclofenac. For more severe pain your doctor may also prescribe nefopam or an ‘opiate’ (like codeine or tramadol) for short-term use. For nerve pain, you might be prescribed a different type of medicine like amitriptyline or gabapentin. For inflammatory pain, you might be given a steroid tablet or injection.

Oral steroids are sometimes prescribed when other medications to reduce inflammation in Rheumatoid Arthritis, and other inflammatory arthritis, have not adequately reduced pain. While steroids work very well, they are recommended as a temporary solution due to long-term side effects and they do not prevent joint damage that is typical in inflammatory arthritis.


How each type of pain medicine works

  • NSAIDs reduce the amount of pain-producing chemicals that your body makes. Examples are ibuprofen and diclofenac.
  • Paracetamol slows the rate at which those pain messages travel along the nerves.
  • Tricyclic antidepressants interfere with the way the pain messages are passed along the nerves. The pain message is reduced as it passes each junction in the nerve, so your perception of pain is less. Amitriptyline and nortriptyline are commonly used for nerve pain, especially pain that keeps you awake at night.
  • Gabapentin, pregabalin or carbamazepine are for nerve pain. These medicines were originally introduced to manage seizures and are believed to interfere with how the messages are transferred from one set of nerve fibres to the next.
  • Steroids like steroid injections or a course of prednisone can reduce the inflammation that starts the pain signals.
  • Opiates include tramadol, codeine, fentanyl, and oxycodone work in your brain to reduce your perception of pain. These tend to be less useful for arthritis or long-term pain but might be used short-term like after a joint replacement.
  • Nefopam is a strong pain relief that works ‘centrally’ to reduce the pain sensation so works a bit like codeine but is not an opiate.
  • Topical non-steroidal anti-inflammatory (Voltaren gel) works like other anti-inflammatories by reducing the amount of pain-producing chemicals that your body makes in response to damage. These might be appropriate if you only have a few joints affected by arthritis.
  • Topical capsaicin work as counter-irritants and nerve desensitizers. With counter-irritants, the burn messages and the pain messages compete with each other on the nerve endings so the amount of pain that can be transmitted is reduced. New research shows that capsaicin has an additional way of working that involves desentisizing some types of nerve endings. Some people find topical capsaicin helpful, though others find the burning sensation too much to cope with.


Drug and medicine names

Now is a good time to mention that all medicines have more than one name. A generic name and a brand name. The generic name is the name of the medicine itself. The brand name is the name that a particular company calls that medicine. Many people know ‘paracetamol’ (the generic name) and ‘Panadol’ or ‘Pamol’ (two different brands). All of these contain the same drug and might be different strengths so be really aware of what you are taking. NSAIDs like Nurofen and Voltaren can be purchased by brand name in a pharmacy, but on prescription might be called by their generic name ibuprofen or diclofenac.

Make sure you always know the generic name of all your medicines and the dose. This makes it easier to check if you buy anything off the shelf in the pharmacy. If you have a head cold and buy cold medicines, they often have paracetamol in them or an anti-inflammatory (NSAID). Always read the packets and make sure you are not doubling up on any of the medicines you are taking as this could make you sick. Also look at the list below so you know all the currently funded NSAIDs. You should not be taking more than one NSAID at any time. If you are unsure, please check with your pharmacist. It is best to always use the same pharmacy if at all possible, as they have your current medicine list. That way you can always ask the pharmacist to check it’s safe when you want to buy any medicine or natural product in the shop.

Knowing the generic name also means it’s easier to understand when Pharmac start funding a different brand compared to what you were on e.g. Voltaren years ago changed to diclofenac Sandoz or Dr Reddy diclofenac; but we still have Voltaren D as a dispersible form of diclofenac and Voltaren brand of suppositories. There are constant changes in what is funded in New Zealand. If you think your medicine has changed but the pharmacist hasn’t told you, always check.

What NSAID pain medicine does Pharmac fund?

NSAIDs currently funded by Pharmac to reduce inflammation are:

  • Diclofenac (one brand name Voltaren)
  • Ibuprofen (one brand name Nurofen)
  • Ketoprofen
  • Naproxen (one brand name is Naprosyn)
  • Tenoxicam
  • Mefenamic acid. Mefenamic acid is mainly used for period pains, but it is an anti-inflammatory and NSAIDs all work in similar ways.
  • Celecoxib. This one is a different type of NSAID called a COX-2 inhibitor. They tend to give the same pain relief with less chance of stomach upsets.

NSAIDs have been shown to give about twice as much pain relief as paracetamol as well as result in greater improvements in function and stiffness. The choice of NSAID is personal. Nothing works for everyone, and some people find one much more effective for them than another. Some people find stomach upset a problem, so need to use celecoxib. Don’t be afraid to ask your doctor to try a different anti-inflammatory. As you can see there are several to choose from. There are also combination medicines with codeine plus an anti-inflammatory or codeine plus paracetamol. Make sure you never double up on your paracetamol and never take more than one type of anti-inflammatory at a time.

Most advice about arthritic pain suggests considering other measures of improvement besides just pain relief. Things like improved function and strength. The advice also suggests that under-treating pain is just as bad as over-treating pain.

Never share pain medicines

The final word from a pharmacist is: Don’t share medicines. The specific medicines that work for you will be different from other people. Your dose is likely to be different than your friend or neighbour for lots of reasons: other health conditions, other medicines, kidney function, age, ethnicity. Some specialists believe some anti-inflammatories have less side effects on your heart; others say they are all fairly similar. What is safe for you might not be safe for your neighbour.

This page was written by Registered Pharmacist, Linda Caddick. June 2024.


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