Methotrexate (MTX) plays a crucial role in the treatment of moderate-to-severe psoriasis. Thanks to numerous long-term observations and control clinical studies its safety and efficacy profile is well-established. Oral route of administration is the most common but data indicate the benefits of subcutaneous injections of MTX. Recent studies have revealed that bioavailability of oral MTX show interindividual differencies and decreases with the dose. In many cases to control disease activity MTX exceeding 15 mg/week is needed. On the other hand high doses of MTX increase the risk of gastro-intestinal side effects, and in some patients, may by ineffective. Bioavailability of subcutaneous MTX is linear and predictable. Studies show that methotrexate in this formulation is more efficacious. Thus it seems reasonable to switch from oral to subcutaneous route of MTX administration specially in patients with treatment failure with MTX or/and with gastrointestinal intolerance. Therapeutic success with this formulation may contribute to postpone the use of much more expensive biologic therapies. Formulation consisting prefilled syringe with high concentration of MTX and pre-attached needleis especially suitable for methotrexate subcutaneousself-administration.
Keywords: bioavailability; methotrexate; route of administration; subcutaneous injections.