Is metformin effective in treating hidradenitis suppurativa?

Metformin for Hidradenitis Suppurativa Treatment

Metformin is an effective, well-tolerated, and inexpensive treatment option for hidradenitis suppurativa (HS), particularly in patients with metabolic comorbidities such as insulin resistance. 1 It can be used as an adjunctive therapy alongside first-line treatments for HS, with clinical response observed in approximately 68% of patients.

Mechanism of Action in HS

Metformin works through multiple mechanisms that may benefit HS patients:

• Reduces inflammatory cytokines implicated in HS pathogenesis (TNF-α, IL-17) 2
• Induces immunometabolic reprogramming 3
• Improves cardiovascular risk biomarkers 4
• May act via the NLRP3 inflammasome and AMPK-mTOR pathway 3

Clinical Evidence for Efficacy

• A retrospective chart review of 53 HS patients showed:

  • 68% experienced subjective clinical response
  • 19% achieved quiescent disease with metformin monotherapy
  • 6-month drug survival rate of 61%
  • 12-month drug survival rate of 39% 1

• Metformin has demonstrated promising results across multiple studies with a favorable safety profile 5

Patient Selection and Considerations

Metformin is particularly beneficial for HS patients with:

• Obesity
• Metabolic syndrome
• Diabetes mellitus
• Insulin resistance (present in 75% of HS patients in one study) 1
• Polycystic ovarian syndrome

Dosing and Administration

• Mean effective dose: 1.5 g/day 1
• Typical treatment duration: Start with a lower dose and titrate up based on tolerance and response
• Monitor for gastrointestinal side effects (reported in 11% of patients) 1

Special Considerations

According to the North American Clinical Practice Guidelines for HS, metformin:

• Reduces tuberculosis risk by 50-75% in diabetic patients
• Is the preferred anti-androgen for HS patients at high risk for TB 6
• Can be safely used in patients with hepatitis B/C, unlike some other treatments that carry hepatotoxicity risks 6

Limitations and Monitoring

• Not all patients respond to metformin therapy (25% showed no improvement in one study) 1
• The presence of insulin resistance does not predict clinical response 1
• Monitor for gastrointestinal side effects, which are typically mild and transient 2

Integration with Other Treatments

Metformin can be used as:

• Monotherapy in mild cases with metabolic comorbidities
• Adjunctive therapy alongside standard treatments based on Hurley staging:
  • For mild disease (Hurley I): alongside topical therapies or tetracyclines 7
  • For moderate disease (Hurley II): alongside clindamycin + rifampin or biologics 7
  • For severe disease (Hurley III): alongside biologics like adalimumab 7

Metformin represents a valuable addition to the HS treatment armamentarium, particularly for patients with metabolic comorbidities, and should be considered as part of a comprehensive treatment approach.