Inadequate response or intolerability to oral methotrexate: Is it optimal to switch to subcutaneous methotrexate prior to considering therapy with biologics?

Methotrexate (MTX) is considered an anchor drug in the treatment of rheumatoid arthritis. It is also the first-line therapy in a multitude of rheumatologic conditions. Low-dose oral MTX is the preliminary modality of treatment for rheumatoid arthritis due to its affordability, favorable outcomes, and limited risks. However, patients refractory to low-dose MTX therapy may require larger doses of oral MTX. Several studies in the past have demonstrated variability in bioavailability of oral MTX at high doses. This warrants a subsequent switch to parenteral MTX. Widely used among the parenteral preparations of MTX is subcutaneous (SC) MTX. SC MTX provides dependable efficacy, predictable bioavailability, sustained clinical outcomes, and minimal GI adverse effects. It is useful either singularly or in combination therapy regimens. Although SC MTX and intramuscular MTX have similar pharmacokinetics, SC MTX may be preferred by most patients. Development of prefilled syringes and auto-injectors have enabled self-administration of the medication providing the patients with a sense of independence and improved general well-being. Hence, SC MTX can prove to be more efficacious in patients refractory to oral MTX therapy or in patients experiencing severe gastrointestinal adverse effects.