Kristine Kucera, PA-C, MPAS, DHS
Treating pediatric patients with inflammatory skin disease often can be challenging. Without published treatment guidelines, clinicians may be uncomfortable prescribing methotrexate (MTX) in this population. To address this unmet need, an expert consensus committee was convened to develop evidence- and consensus-based guidelines for the use of MTX in pediatric patients. These recommendations will support safe and effective use of MTX for the underserved population of pediatric patients who may benefit from this valuable medication.
I generally start with MTX ~15mg/week given as a once weekly dosage of six 2.5mg tablets (see below for weight-based dosing). I also have the patient take folic acid six days a week skipping the day the methotrexate is dosed. Baseline labs include comprehensive metabolic panel (CMP) complete blood count (CBC). Monitoring labs are drawn at week 1, week 4, and then every 12 weeks if stable.
The key points are listed below and full access to the guidelines can be found in Pediatric Dermatology online.
Kristine Kucera, PA-C, MPAS, DHS, is Assistant Clinical Professor, University of Texas Southwestern, Medical Center PA Program, Dallas, TX. She is a member of the DEF Advisory Council.
Reference:
https://onlinelibrary.wiley.com/doi/10.1111/pde.15327
Key Consensus Statements
— doi.org/10.1111/pde.15327
- Typical MTX dose varies, but the maximum dose for inflammatory skin disease is considered to be 1 mg/kg, not to exceed 25 mg/week.
- Test doses are not necessary for pediatric patients starting low-dose (≤1 mg/kg) MTX for inflammatory skin disease.
- Onset of MTX efficacy may be 8–16 weeks.
- MTX can be discontinued abruptly without adverse effects, other than risk of disease worsening.
- Folic acid supplementation (starting at 1 mg/day, regardless of weight) is an effective approach to minimizing associated gastrointestinal adverse effects.
- Concomitant use of MTX and antibiotics (including TMP/S) and NSAIDS are not contraindicated for most pediatric patients treated for inflammatory skin disease.
- Live virus vaccine boosters (e.g., VZV and MMR) are not contraindicated for patients taking MTX; there are insufficient data to make recommendations for or against primary immunization with MMR vaccine in patients taking MTX; inactivated vaccines should be given to patients taking MTX.
- Routine surveillance laboratory monitoring (i.e., CBC with differential, ALT, AST, creatinine) is recommended at baseline, after 1 month of treatment, and every 3–4 months thereafter.
- Transient transaminase elevation (≤3× ULN for <3 months) is not uncommon with low-dose MTX and does not usually require MTX interruption. The most likely causes are concomitant viral infection, MTX dosing within 24 h prior to phlebotomy, recent administration of other medications (e.g., acetaminophen), and/or recent alcohol consumption.
- Liver biopsy is not indicated for routine monitoring of pediatric patients taking low-dose MTX.