Osteoarthritis (OA) is a degenerative disorder involving wear and tear of the joints. It generally presents during middle age and most commonly affects the hip, knee, spine and small joints of the hand. Risk factors for developing the condition include familial history of OA, increasing age, previous injury to a joint and comorbidities such as gout and obesity.
It is estimated that there are approximately 8.5 million people in the UK suffering with OA, and two-thirds of these patients are in constant pain. Pharmacists are well placed to assist patients in managing their pain effectively during a medicines use review.
Nice guidance recommends oral non-steroidal anti-inflammatory drugs (NSAIDS), either non-selective or cyclo-oxygenase-2 (cox-2) inhibitors, prescribed with a proton pump inhibitor (PPI) as second-line treatment for OA pain. These may be adjunct or a substitute to first-line paracetamol, depending on an individual’s response. Topical NSAIDs are also recommended for initial treatment but should not be used concurrently with oral NSAIDs.
The non-selective NSAIDs or cox-2 inhibitors should be used at the lowest effective dose for the shortest possible period. Choice of NSAID is based on the patient’s comorbidities such as age, concomitant medication, cardiovascular disease, renal function and history of peptic ulcer disease, and also the differing side effect profile of each drug. There is some increased cardiovascular risk for chronic users of high dose NSAIDs, especially with cox-2 inhibitors and diclofenac. Naproxen is associated with a lower thrombotic risk than the cox-2 inhibitors.
In patients taking low-dose aspirin for prevention of cardiovascular disease, alternative analgesics (eg opioids, or topical capsaicin with regular paracetamol) are recommended initially before substituting or adding a non-selective NSAID or cox-2 inhibitor.
PPIs are routinely co-prescribed with NSAIDs to prevent gastrointestinal (GI) irritation due to inhibition of prostaglandins. Cox-2 selective inhibitors such as celecoxib are more suitable in patients with a history of GI ulceration/bleeding.
Ultimately, chronic, debilitating pain that is unresponsive to NSAIDs should be reviewed by the patient’s GP. Step-up treatments - including topical capsaicin, oral opioids such as codeine, low-dose tricyclic antidepressants (TCAs) and intra-articular corticosteroid injections - can be of benefit in poorly controlled joint pain. Joint replacement surgery is indicated in severe cases.
NSAIDs are generally not recommended for people with kidney disease, heart failure, cirrhosis or for people who take diuretics.
Patients with asthma can usually use NSAIDs if they have taken them previously, although drug-induced bronchospasm is a concern.
Some patients who are allergic to aspirin may be able to take selective NSAIDs safely.
Key information for patients
Patients should be informed that there is no prevention or cure for OA at present and pharmacological treatments offer symptomatic relief only.
Patients should be guided by their pharmacist on what to expect from NSAID therapy. Differences in anti-inflammatory activity are small, but there is considerable variation in individual response and tolerance to these drugs. About 60 per cent of patients will respond to any NSAID; of the others, those who do not respond to one may well respond to another.
Each treatment should be given an adequate therapeutic trial before changing to an alternative; patients should be informed that pain relief will begin soon after taking the first dose and a full analgesic effect should be achieved in one week, while an anti-inflammatory effect may not be achieved for at least three weeks. If appropriate responses are not obtained within these times, the dose may be gradually increased or another NSAID should be tried.
Pharmacists should remind patients that only one NSAID (oral, topical or rectal) should be used at a time in order to prevent adverse effects and toxicity.
Patients should be informed of the rationale for taking a PPI and made aware of troublesome GI symptoms to be reported to their doctor if experienced. NSAIDs should always be taken with, or soon after, food to reduce the risk of irritation and ulceration of the stomach lining.
Pharmacists can encourage positive lifestyle changes, which are the mainstay of treatment:
- Weight loss, particularly for obese patients, has shown to improve both pain and physical function.
- Regular exercise: muscle strengthening, manipulation and stretching.
- Appropriate footwear with shock-absorbing soles.
- Assistive devices, such as walking sticks and home adjustments.
- Measures to protect joints, such as a thumb splint.
Sarah McBride is a locum pharmacist based in London
- Nice (2014) Osteoarthritis: Care and management in adults. Nice clinical guideline 177.
- Arthritis Research UK