Abstract Number: 28

Methotrexate – An expert position statement

M. Rademaker, M. Gupta, J. Sullivan

Meeting: 2016 Dermcoll

Session Information

Date: -

Session Title: Clinical Updates

Session Time: -

The Australasian Psoriasis Collaborative considered the position of methotrexate (MTX) in the treatment of psoria- sis in the Australasian context.

MTX is antiinflammatory, inhibiting 5-aminoimidazole-4- carboxamide ribonucleotide transformylase, and has mini- mal immunosuppressive effects in low dose.

Prior to starting MTX it is appropriate to measure full blood count, renal and liver function, HbA1c, and non-fast- ing lipids. Record body mass index, weight, and abdominal circumference. Additional tests in at risk patients may include screening for TB (Quantiferon Gold, CXR), Hepati- tis B/C, HIV, and varicella zoster serology.

In uncomplicated patients repeat FBC: at 2 and 4 weeks, then every 3 months. Renal and liver function tests, non- fasting lipids, HbA1c may be repeated every 6–12 months.

Standard dermatological dose is 15–25 mg once per week (range 5–40 mg/week), with no consensus on the need for a test dose, or limitation to a maximum cumulative dose. Con- sider subcutaneous MTX if poor compliance or GI adverse effects. It takes 4–6 months to fully polyglutaminate MTX.

Methotrexate has a low inherent risk of liver toxicity. The majority of treatment emergent liver toxicity is related to underlying metabolic syndrome. A high HbA1c is more pre- dictive of death than a persistently high ALT. Liver biop- sies are rarely required. Consider a FibroScan within 6/12, repeated in 1–3 years. Alcohol itself is not contraindicated, but limit to <1–2 standard drinks/day. Methotrexate can be used in conjunction with most other 2nd line agents. Safety in pregnancy and lactation has not been established; paternal exposure remains controversial, but is likely safe.