What is oral PUVA (Psoralen and Ultraviolet A) therapy?

What is Oral PUVA?

Oral PUVA (Psoralen plus Ultraviolet A) therapy is a photochemotherapy that involves taking psoralen medication by mouth followed by exposure to UVA light, typically 1-2 hours after ingestion, to treat various skin conditions including psoriasis, mycosis fungoides, and other dermatoses. 1

Components of Oral PUVA

Psoralen Medication

• Types of oral psoralen:

  • 8-methoxypsoralen (8-MOP): Taken 2 hours before UVA exposure
  • 5-methoxypsoralen (5-MOP): Used when patients experience excessive nausea with 8-MOP
  • Oxsoralen-Ultra: Taken 1-1.5 hours before UVA exposure 1

• Dosing:

  • Based on patient's body weight/surface area
  • Typically administered as microcrystalline tablets or liquid in capsules 1
  • Dose must be adjusted if patient gains or loses significant weight 1

Administration Protocol

• Timing: UVA exposure occurs 1-2 hours after oral psoralen ingestion (specific timing depends on psoralen type) 1
• Frequency: Treatments usually given 2-3 times weekly with at least 48 hours between sessions 1
• Duration: Continued until clinical clearance, then gradually tapered to maintenance regimen 1

Clinical Considerations

Advantages of Oral PUVA vs. Topical PUVA

• Shorter overall outpatient attendance times
• Less staff involvement
• Lower risk of phototoxic reactions from natural UV exposure after treatment
• Practical for whole-body treatment when bath facilities are inadequate 1

Management of Side Effects

• Nausea: Common with oral psoralen, can be minimized by:
  • Taking medication with milk, crackers, or a meal
  • Maintaining consistent food intake with each dose (as food affects absorption)
  • In severe cases, anti-nausea medication 30-60 minutes before psoralen 1
  • Switching to 5-MOP if 8-MOP causes excessive nausea 1

Safety Precautions

• Eye protection: UVA-opaque sunglasses required during and after treatment (for 12-24 hours) to prevent cataract formation 2
• Genital shielding: Essential to reduce risk of genital squamous cell carcinomas 2
• Sun protection: Sunscreen use, protective clothing, and avoidance of sun exposure during treatment period 1

Treatment Response

• Most patients see response within 1 month of treatment 1
• Efficacy comparable to bath PUVA for conditions like psoriasis 3
• For chronic plaque psoriasis, PUVA should usually be offered before oral systemic therapy if NB-UVB has been ineffective 1

Important Considerations and Precautions

• Careful patient selection is mandatory - those with chronic actinic damage or history of skin cancer may have higher risk of developing new cancers 2
• Long-term risks increase with cumulative exposure (threshold for nonmelanoma skin cancer risk: 200 treatments or 1200 J/cm² total UVA dose) 2
• Annual dermatological examinations recommended for early detection of skin cancer 2
• No sun tanning or tanning beds should be used during treatment period 1

Oral PUVA remains an important treatment option, particularly as second-line phototherapy for chronic dermatoses when narrowband UVB has failed, or as first-line therapy for specific conditions like plaque-stage mycosis fungoides and pityriasis rubra pilaris 1.