In ankylosing spondylitis (AS), the ligaments or tendons attached to the spine become inflamed and gradually become replaced with bone. This leads to the spinal vertebrae fusing, making movement difficult.

Non-steroidal anti-inflammatory drugs (NSAIDs: aceclofenac, acemetacin, azapropazone, celecoxib, dexibuprofen, diclofenac, fenbufen, fenoprofen, flurbiprofen, ibuprofen, indometacin, ketoprofen, meloxicam, naproxen, piroxicam, sulindac, tenoxicam, tiaprofenic acid) are the mainstay of treatment, but disease-modifying anti-rheumatic drugs may also be used (though usually unlicensed).

Long-term oral corticosteroids should not be used, but short-term high doses or injections may have a role in therapy. Severe AS may be treated using a cytokine inhibitor (adalimumab, etanercept, infliximab).

Dosage regimen

* NSAIDs are usually taken in divided doses throughout the day. The product SPC should be checked for details.

* DMARD doses vary greatly. Sulfasalazine, the most commonly used, may be taken in doses of up to 3g a day. The dose of methotrexate can be up to 30mg a week, with an accompanying folic acid dose of 5mg one one day per week.

* Local corticosteroid injections of methylprednisolone are given as an 80mg or 120mg dose. In exacerbations, up to 5mg prednisolone is given daily in tablet form.

* The cytokine inhibitor infliximab is given by intravenous infusion every 6 weeks or so. The other two commonly used cytokine blockers etanercept and adalimumab are given by subcutaneous injection, etanercept usually twice weekly, and adalimumab weekly or every other week.

Patient’s knowledge of the medicine’s use

* Does the patient know that NSAIDs only provide symptomatic relief? They may not understand that they will not cure or control the disease.

* DMARDs do affect the progression of the disease, but it can take two to six months before a full effect is seen.

* Corticosteroids, both injectable and oral, reduce inflammation.

Is the medicine working?

* Does the patient feel that their condition is not being controlled or that it is worsening? If so, they should be referred to their GP. There are many different types of treatment available, if one does not work, another one may.

Side effects

* NSAIDs commonly cause GI side effects, such as nausea and diarrhoea. Suspected ulceration or bleeding should be referred. There is also an increased risk of thrombotic events (stroke, myocardial infarction), particularly with Cox-2 inhibitors, but also with any long-term, high-dose NSAID.

* Sulfasalazine is related to aspirin, so may cause GI disturbances and rash. It is also associated with blood dyscrasias, so patients should be warned to report any unexplained bleeding, bruising, sore throat or malaise.

* Methotrexate can cause abdominal discomfort and anorexia. Rarer side effects include blood dyscrasias and heptotoxicity, so patients should be advised to report any signs suggestive of an infection, especially a sore throat.

* Methylprednisolone may cause an inflammatory reaction at the site of the injection.

* Cytokine inhibitors can cause severe infections such as septicaemia and tuberculosis. If severe side effects develop, the drug should be withdrawn. Other, more common, side effects include nausea and abdominal pain. Etanercept can cause neutropenia, so patients should be advised to report any symptoms suggestive of infection, such as fever or sore throat.

Monitoring

* Patients taking sulfasalazine must have regular tests to exclude blood dyscrasias.

* Patients taking methotrexate should have regular blood, renal and liver function tests done as this drug can cause liver cirrhosis and blood dyscrasias. 

* Patients on adalimumab and infliximab should be checked for active and latent TB before starting treatment. Patients with active TB should not receive either drug, but latent TB sufferers may if chemoprophylaxis is started beforehand.

* Patients on etanercept should have a neutrophil count taken before starting treatment, then every month for six months, then every three months thereafter. This is to exclude neutropenia.

Lifestyle

* Advise the patient to try heat pads or a hot water bottle as this can help alleviate pain and stiffness.

* If the patient is overweight, advise on the benefits of losing weight as this will reduce the excess pressure being placed on weight-bearing limbs.

* Gentle exercise such as swimming can help keep limbs mobile. 

 

Uzma Chaudhry, relief pharmacist, Lloydspharmacy, Oxfordshire/AF

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