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Understanding pain relief medication

What is pain?

Pain is one of the body's protective mechanisms. It acts as a warning sign to alert you to situations or actions that may be causing damage to your body so that you can act to avoid the situation or stop the action. Pain is the way your brain interprets information about a particular
sensation that your body is experiencing. Signals are sent via nerve pathways to your brain.

Because perception and tolerance of pain can vary widely between individuals, that which is very painful for one person may be only moderately painful for another. In addition, the way in which your own brain interprets these signals can also be affected by many factors and so what is painful to you one day, may be less so on a different day.

Pain is usually categorised as being either acute or chronic.

Acute pain starts suddenly and tends to be short-lived, but may last up to 3 months. Acute pain has an identifiable cause and purpose and the pain gradually disappears through the process of normal healing.

Chronic or persistent pain by definition persists for more than six months, beyond the normal time of healing, and can sometimes last for years. Chronic pain may be the result of a specific injury or an ongoing medical problem or sometimes there may be no obvious cause. The pain associated
with osteoarthritis is usually chronic pain.

Why is pain management important?

Being in constant pain will often affect other aspects of your life such as the ability to sleep soundly, the ability to work, it can lead to emotional distress and may cause strain on relationships. The treatment for chronic pain differs from that of acute pain. The medication choices that are appropriate for acute pain may not be the best choice for treating chronic pain. Some medications, because of their associated side effects, should only be used for the short term and as such are not recommended for treating chronic pain. Often non-medicated treatments can work as well as, if not better than, some medications for treating chronic pain.

Osteoarthritis (OA) can be a very painful condition. As someone with osteoarthritis, it is important that you work with your healthcare team to find the best combination of medicines and non-medicated treatments that will work for you, to minimise the pain and disability you experience. There are a number of non-medicated techniques for dealing with the pain of OA, which are detailed in the education module called “Non-Medicated Pain Management” which you should review if you haven’t already done so. However it is also important to understand what types of medications are recommended to be used to prevent and to treat the pain of OA.

There are a number of medicines your doctor may choose to recommend for you and their choice of medications will depend on how severe your pain is, any other medicines you might be taking, and any other health conditions you may have. Often they will recommend a combination of medications to best treat both the pain and inflammation that is associated with OA.

Pain relieving medications (analgesics)

Pain relieving medications work by inhibiting or blocking the brain’s perception of pain. They don’t stop the damage that is causing the pain but they do reduce the sensations that are relayed via the nervous system back to the pain centre of the brain, enough so that functions of daily living can still be performed.

Potential Side Effects

Any medication that has a therapeutic effect also has the potential to cause unwanted or adverse side effects. To find out more about the potential side effects of the medications you take, ask your pharmacist for a Consumer Medication Information leaflet and discuss with them the information contained within it.


The national treatment guidelines recommend the first choice for pain relief in patients with osteoarthritis of the hip or knee should be paracetamol. It should be taken regularly in divided doses throughout the day up to a maximum of 4 g/day. Taking more than this won’t produce better pain relief.
Paracetamol is usually well tolerated, produces few side effects when used at the recommended dose and gives very good pain relief when
taken as directed. Many people for whom paracetamol does not 'work' are either not taking enough or not taking it regularly to prevent “break through” pain.

Taking paracetamol regularly means taking it when the dose is due according to the clock, not waiting until you are in discomfort. If you know that certain activities tend to cause you pain, like taking the dog for a walk, have your dose of paracetamol half an hour before commencing the
activity and repeat the dose again at the appropriate interval. This way you will maintain better control of your pain.

Slow-release tablets are now available so the dosage can be taken fewer times a day. To prevent accidentally taking too much paracetamol, it is important that you check the list of active ingredients on the label of any other over-the-counter medicines you intend taking, and speak to your pharmacist about them, as many products do contain paracetamol in combination such as cold and flu medicines.

NSAIDs (Non-steroidal Anti-inflammatory Drugs)

If your pain is not well controlled with paracetamol, usually the doctor will prescribe an NSAID as the next step in pain relief where appropriate. Common brand names for over-the-counter NSAIDs include Nurofen® or Voltaren®. In addition to relieving pain, NSAIDs also reduce inflammation and swelling so are very effective treatments for osteoarthritis.

Due to their potential for side effects, especially gastro-intestinal effects, these medications may not be appropriate for some. In recent years, a new group of prescription only NSAIDs has appeared on the market (eg Celebrex® and Mobic®) which are said to be better tolerated in most people. The GP will still usually closely monitor blood pressure and kidney function of some patients whilst they are taking NSAIDs to prevent complications.

NSAIDs will also interact with certain other medications and some health conditions and it is for these reasons that NSAIDs are usually recommended only for short bursts of treatment when other pain relief is inadequate. It is not uncommon for someone to be taking both paracetamol and a low dose of an NSAID to treat a flare up of their knee or hip pain.


For those experiencing severe pain that has not responded to other medications, and for those who haven’t been able to tolerate other medications, the next choice in pain relievers are opioids, such as codeine. These medications are very effective pain relievers but they also tend to have
significant side effects and can be addictive so for that reason are not considered as the first choice, and would only be used if other alternatives have been tried and proven ineffective or are inappropriate. Again the GP will usually closely monitor anyone taking an opioid analgesic to ensure the benefits of treatment outweigh the risks of adverse events.


An Intra-articular injection (IA) of corticosteroid directly into the joint is sometimes appropriate for short term symptom relief of an acutely painful, swollen joint.  The injection of a steroid reduces inflammation in the joint and therefore reduces pain. There is the potential that repeated steroidal IA injections can result in possible cartilage damage so the number of injections a patient receives is generally limited to three times per year for large weight bearing joints (eg knees and hips) and four times a year for smaller joints (eg toes, fingers, etc).

Viscosupplementation is the name given to a procedure of injecting synthetic hyaluronic acid or hylan (HA) products into a joint via IA injection. Hyaluronic acid is a naturally occurring substance found in joints that provides lubrication. In patients with OA of the knee, the amount and quality of naturally produced HA is reduced, so the aim of supplementation with synthetic HA, is to improve mobility and reduce friction thereby reducing pain. There is no evidence that there is any benefit to people with OA of the hip receiving these types of injections.

Anti-inflammatory Creams & Gels  

Massaging a cream or gel containing an NSAID into the skin over an affected joint allows the medication to be absorbed into the tissue immediately surrounding the joint, which results in an increased concentration of the drug locally to the joint. The benefit of this is that, by rubbing the cream on the skin, the drug by-passes the stomach so there is a much lower risk of gastro-intestinal side effects and medication interactions compared to NSAIDs in tablet form.

Creams and gels are often recommended for short term use by patients with knee OA, whereas their effectiveness in hip pain is lower because the hip joint is not as close to the skin surface as the knee is and the medication does not penetrate deeply enough to provide relief.

Complementary Medicines

“Many of the nutritional supplements available today claim to have benefits for those with osteoarthritis, but it is important to remember that the research in this field can be scanty and poorly conducted compared to the vigorous field of conventional medicine. Dietitians would agree that most vitamins can be acquired through a healthy diet of fresh fruit and vegetables, fish oils and natural sunshine, and that overdosing could occur if unnecessary supplements are taken above the required diet.

Although some clinicians are not convinced of the benefit of glucosamine and chondroitin in relation to osteoarthritis, in general they have a high safety record and it is accepted that these two supplements can be considered for those with osteoarthritis. Each individual is responsible for what they choose to take and are advised to research their benefits before investing in this field. Medications used in other diseases should not be stopped without first discussing this with your doctor.”

Ref. Arden E., Arden N., Hunter D. (2008). Osteoarthritis: thefacts. United States: Oxford University Press Inc., New York.


IMPORTANT: This information has been provided to give a brief description of some of the medications you may come across in relation to osteoarthritis. It is not designed to replace the advice or recommendations given to you by your doctor or other members of your supervising healthcare team. Please consult your GP or health care provider if you have a specific query in regards any medications.