Who should consider oral minoxidil for androgenetic alopecia or alopecia areata?

Oral Minoxidil for Hair Loss: Patient Selection Guidelines

Oral minoxidil should be considered primarily for patients with androgenetic alopecia who have failed or are intolerant to topical minoxidil, with dosing between 0.25-5mg daily, after careful cardiovascular screening. 1, 2

Appropriate Candidates for Oral Minoxidil

Primary Indications

• Androgenetic Alopecia (AGA)

  • Most robust evidence supports use in AGA with 61-100% of patients showing objective improvement 2
  • Can be effective in both male and female pattern hair loss 1, 2
  • Consider when topical minoxidil has failed or patient compliance is poor 2

• Alopecia Areata (AA)

  • Variable efficacy (18-82.4% improvement) 2
  • Less effective than contact immunotherapy for severe AA 3, 1
  • May be considered for patients who cannot tolerate other treatments

Secondary Indications (Limited Evidence)

• Chronic telogen effluvium
• Monilethrix
• Permanent chemotherapy-induced alopecia 2

Patient Selection Criteria

Required Pre-Treatment Assessment

• Cardiovascular screening:

  • Blood pressure measurement (avoid in severe hypertension)
  • Assessment for risk of cardiovascular events
  • Evaluation for potential pedal edema 4

• Laboratory investigations:

  • Consider baseline thyroid function tests (TSH, Free T4)
  • Vitamin D levels (target >75 nmol/L)
  • Serum/plasma zinc and copper levels
  • Vitamin B12 and folate levels 1

Contraindications

• Absolute contraindications:

  • Pregnancy and breastfeeding
  • Age under 18 years 1
  • Severe uncontrolled hypertension 4

• Relative contraindications:

  • Scalp conditions that may increase absorption
  • History of significant hypotension
  • Pre-existing cardiovascular disease 1, 4

Dosing Recommendations

• Starting dose: 0.25-1mg daily
• Maintenance dose: 0.25-5mg daily or divided twice daily 2
• Optimal dose for males with AGA: 5mg once daily showed significant efficacy in clinical trials 4
• Dose for females: Generally lower (0.25-2.5mg) to minimize hypertrichosis 2

Monitoring and Follow-up

• Baseline photos before starting treatment
• Initial evaluation at 3 months
• Critical assessment at 6 months
• Comprehensive review at 12 months 1
• Regular blood pressure monitoring during treatment

Common Side Effects to Discuss with Patients

• Hypertrichosis (93% of patients) - most common side effect 4
• Postural hypotension - second most common 2
• Pedal edema (10% of patients) 4
• Sexual dysfunction (rare with low doses)

Important Considerations for Special Populations

• Men undergoing prostate cancer screening:

  • Oral minoxidil may affect PSA levels
  • Consider baseline PSA before starting treatment 1

• Women of childbearing potential:

  • Must use reliable contraception
  • Regular pregnancy tests may be advisable 1

Practical Advantages Over Topical Minoxidil

• Improved patient compliance
• Avoids scalp irritation from topical formulations
• More consistent drug delivery 2

Comparative Efficacy

While oral finasteride (1mg daily) has shown higher clinical cure rates (80%) compared to topical minoxidil 5% (52%) in male AGA 5, oral minoxidil offers an alternative for those who:

• Cannot tolerate finasteride side effects
• Have failed finasteride treatment
• Have contraindications to finasteride use

Oral minoxidil represents an effective treatment option with a favorable safety profile when used at appropriate doses in carefully selected patients with proper monitoring.