Special features

Psoriasis arthritis — treatment approaches

By Richard Copeland, MPhil, MRPharmS, Fraser Birrell, PhD, FRCP, and Alan Worsley, PhD, MRPharmS

Psoriatic arthritis is a potentially destructive arthropathy. This article discusses treatments for the condition, how the effect of treatment is assessed and issues for hospital pharmacists to consider when dealing with patients who suffer from the condition

FULL TEXT article PDF (60K)

Dosages of DMARDs used to treat psoriatic arthritis

Richard Copeland is a specialist pharmacist in rheumatolog

Fraser Birrell is a consultant rheumatologist

both at Northumbria Healthcare NHS Foundation Trust

Alan Worsley is a senior lecturer in pharmacy practice at the University of Sunderland

JOHN KAPRIELIAN/SPL

Adalimumab is administered every fortnight in the treatment of psoriasis arthritis

Adalimumab is administered every fortnight in the treatment of PsA

SUMMARY

Treatment options for psoriatic arthritis (PsA) tend to mirror those for rheumatoid arthritis or ankylosing spondylitis, depending on the location of the joints affected.

The evidence for treating PsA is limited, particularly in comparison with rheumatoid arthritis.

However, guidance from the National Institute for Health and Clinical Excellence outlines a treatment approach based upon the best evidence available.

Dosages of DMARDs (Disease modifying antirheumatic drugs ) used to treat psoriatic arthritis

Methotrexate — dose usually given weekly, up to 25mg if tolerated, following a rapid dose escalation. The drug is cleared renally, so doses may require alteration as a result of renal impairment.

Sulfasalazine — dose usually increased over four weeks to 1g twice a day, and further increased (if tolerated) to 1.5g twice a day (or 1g three times a day), to control peripheral joint inflammation.

Leflunomide — maintenance dose either 10mg daily or 20mg daily. A 100mg loading dose is now rarely used. The active metabolite has a long half-life, and a specific washout procedure must be followed if the drug needs to be cleared from the body (eg, due to a severe adverse reaction).