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Phosphodiesterase 4 inhibitors

This is an anti-inflammatory oral treatment (tablet) that works by reducing enzymes in the body called phosphodiesterase 4 inhibitors (PDE4), which are involved in the inflammatory process seen in psoriatic arthritis. The drug improves swollen joints. Women of child-bearing age should avoid becoming pregnant while taking a PDE4 inhibitor. Discuss with your doctor which types of contraception are suitable for you and your partner.

The treatment does contain lactose. There have been reports of an increased risk that some people may experience psychiatric symptoms with PDE4 inhibitors, including depression and suicidal thoughts, therefore close monitoring is required.

The National Institute for Health and Care Excellence (NICE)  recommends taking a PDE4 alone or in combination with disease-modifying antirheumatic drugs (DMARDs), if:

  • there is peripheral arthritis with 3 or more tender joints and 3 or more swollen joints, and
  • if disease has not responded to adequate trials of at least 2 standard DMARDs, given either alone or in combination

PDE4s should be stopped at 16 weeks if the psoriatic arthritis has not shown an adequate response using the Psoriatic Arthritis response Criteria, defined as an improvement in at least 2 of the 4 PsARC criteria (including joint tenderness or swelling score) with no worsening in any criteria