Standard Dosing Schedule for Otrexup
Otrexup, an autoinjector form of methotrexate for rheumatoid arthritis, psoriasis, or polyarticular juvenile idiopathic arthritis, is injected once weekly. Adults typically start at 7.5 mg, with doses adjustable up to 25 mg based on response and tolerance. It's given subcutaneously on the same day each week, often after the lowest white blood cell count day if following chemotherapy protocols.[1]
How to Administer the Injection
Inject into the abdomen or thigh; rotate sites weekly to avoid irritation. The device delivers the dose in seconds with a single push. Refrigerate but allow to warm to room temperature before use. Do not use if solution is discolored or particles are present.[1][2]
Dose Adjustments by Condition
- Rheumatoid arthritis/psoriasis: 7.5–25 mg weekly.
- Juvenile idiopathic arthritis: 15 mg/m² weekly, capped at adult max.
Folic acid supplements (1–5 mg daily, except injection day) reduce side effects like nausea. Liver function tests guide adjustments.[1]
What If a Dose Is Missed?
Inject as soon as possible if within 2 days; otherwise, skip and resume the next scheduled day. Doubling up risks toxicity.[2]
Common Side Effects and Injection Frequency Impact
Weekly dosing minimizes peaks/troughs compared to daily oral methotrexate, but patients report injection-site reactions (redness, pain) in up to 10–20% of cases. Long-term use requires monitoring for liver damage or bone marrow suppression.[1][3]
Alternatives to Weekly Injections
Rasuvo offers similar weekly subcutaneous methotrexate. Oral methotrexate is daily but less bioavailable. Biologics like Humira (every 1–2 weeks) or Xeljanz (daily oral) compete for RA/psoriasis control.[3]
[1]: Otrexup Prescribing Information (DailyMed)
[2]: Antares Pharma Otrexup Guide
[3]: DrugPatentWatch.com - Otrexup Patents