Should women be prescribed lower starting doses of metformin?

  • de Vries ST & al.
  • Drug Saf
  • 11 Feb 2020

  • curated by Miriam Tucker
  • Clinical Essentials
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Takeaway

  • Women report more adverse drug reactions (ADRs) to metformin shortly after initiation vs men and reduce prescribed doses after several months.

Why this matters

  • Metformin is first-line treatment in type 2 diabetes, but ADRs are common.

Study design

  • From Dutch pharmacovigilance database, 1712 patients were asked to complete web-based questionnaires at 2 and 6 weeks and 3, 6, 9, and 12 months after metformin initiation.
  • Funding: ZonMW—The Netherlands Organization for Health Research and Development; European Union.

Key results

  • During follow-up, 46% of women reported ≥1 ADR, compared with 37% of men.
  • Most common ADRs were diarrhea, nausea, abdominal discomfort, flatulence, headache, and fatigue.
  • 34% of women and 25% of men reported ADRs in the first 2 weeks (P<.001>
  • 37% of women vs 28% of men reported ADRs at 6 weeks (P=.001).
  • From 2 weeks to 12 months, the average overall metformin dose increased slightly more for men (830-1161 mg) than women (809-1034 mg).
  • Average doses were higher for men than women throughout, but significantly so only at 9 months (P<.01>

Limitations

  • Only 28% completed all 6 assessments.
  • No information about other patient characteristics (e.g., weight, diabetes duration, kidney function).
  • Questionnaire responders may not represent all metformin users.