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Intramuscular methotrexate-induced aseptic meningitis

John Hawboldt1, Mazen Bader

  • 1School of Pharmacy, Health Sciences Centre, Department of Pharmacy, Eastern Health, St. John's, Newfoundland, Canada. hawboldt@mun.ca

The Annals of Pharmacotherapy
|September 20, 2007
PubMed
Abstract

Insights

This case study reports the first instance of aseptic meningitis in a rheumatoid arthritis patient receiving intramuscular methotrexate. The condition recurred upon drug rechallenge, confirming a probable link.

Area of Science:

  • Neurology
  • Rheumatology
  • Clinical Pharmacology

Background:

  • Methotrexate is a common disease-modifying antirheumatic drug (DMARD).
  • Aseptic meningitis is a rare but serious adverse effect associated with methotrexate, typically reported with intrathecal administration.

Observation:

  • A 62-year-old male with rheumatoid arthritis developed recurrent aseptic meningitis.
  • Symptoms included headache, neck stiffness, and fever, with cerebrospinal fluid findings consistent with meningitis.
  • The patient experienced three episodes of aseptic meningitis, two requiring hospitalization, following intramuscular methotrexate administration, particularly after dose escalation.

Findings:

  • This case represents the first documented instance of aseptic meningitis induced by intramuscular methotrexate.
  • The Naranjo probability scale indicated a probable relationship between methotrexate use and the development of aseptic meningitis.
  • Recurrence of symptoms upon drug rechallenge strongly supports the causal link.

Implications:

  • Clinicians should consider aseptic meningitis in patients with rheumatoid arthritis on intramuscular methotrexate presenting with suggestive symptoms.
  • This finding expands the known adverse effect profile of methotrexate, highlighting potential risks with non-intrathecal routes.
  • Further investigation into the mechanisms of methotrexate-induced aseptic meningitis, even with intramuscular administration, is warranted.

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