Methotrexate Dosing Regimen for Plaque-type Psoriasis: A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation

There is a range of methotrexate dosing regimens for psoriasis. This review summarizes the evidence for test-dose, start-dose, dosing scheme, dose adjustments, maximum dose and use of folic acid. A literature search for randomized controlled trials and guidelines was performed. Twenty-three randomized controlled trials (29 treatment groups) and 10 guidelines were included. Two treatment groups used a test-dose, 5 guidelines recommend it. The methotrexate start-dose in randomized controlled trials varied from 5 to 25 mg/week, most commonly being either 7.5 mg or 15 mg. Guidelines vary from 5 to 15 mg/week. Methotrexate was administered as a single dose or in a Weinstein schedule in 15 and 11 treatment groups, respectively; both recommended equally in guidelines. A fixed dose (n =18), predefined dose (n =3), or dose adjusted on clinical improvement (n=8) was used, the last also being recommended in guidelines. Ten treatment groups used folic acid; in 2 it was allowed, in 14 not mentioned, and in 3 no folic acid was used. Most guidelines recommend the use of folic acid. Authors' suggestions for methotrexate dosing are given.