What is the recommended treatment protocol for a patient with warts using Cidofocir (Cidofovir) cream?

Cidofovir Cream for Warts

Cidofovir cream is NOT a recommended first-line treatment for warts and should only be considered as an alternative therapy for refractory cases that have failed standard treatments. The most recent guidelines classify cidofovir as a low-quality alternative option with limited evidence supporting its use. 1

Guideline Position on Cidofovir

• The British Association of Dermatologists (2014) assigns cidofovir a Level of Evidence 3 and Strength of Recommendation D, indicating weak evidence and limited recommendation for use. 1

• The CDC guidelines (2010) list topical cidofovir only as an alternative regimen for genital warts, not as a primary treatment option. 1

• No major guideline recommends cidofovir as first-line therapy for any type of wart—it is reserved for cases that fail standard treatments. 1

When Cidofovir May Be Considered

Cidofovir should only be considered after failure of established first-line treatments:

• For cutaneous warts: After failure of salicylic acid (15-40%) and cryotherapy. 1

• For genital warts: After failure of podofilox 0.5%, imiquimod 5%, or cryotherapy. 1

• Special populations: Immunocompromised patients (HIV, transplant recipients, chemotherapy patients) with refractory warts may benefit most from cidofovir. 1, 2, 3

Cidofovir Treatment Protocol (When Used)

Topical application protocol:

• Concentration: Reconstituted from parenteral form as either 1% or 3% cream compounded in an unscented moisturizing base. 1

• Application schedule: Applied under occlusion for 5 days per week, followed by 2 days off (one week cycle). 1

• Duration: Cycles repeated for 6-8 weeks or until clearance. 1, 4, 5

• Alternative dosing: Some case reports describe daily application without the 5-days-on/2-days-off cycle, particularly for plantar warts. 6, 2, 5

Intralesional injection protocol:

• Cidofovir can be injected intralesionally, with one open study reporting 98% clearance after an average of 32 injections. 1

Efficacy Data

The evidence for cidofovir is limited to case series and small studies:

• Pediatric cutaneous warts: In a case series of 7 children, 4 achieved complete clearance (57%) after 8 weeks of 1% cidofovir cream. 1

• Plantar warts: A retrospective study of 35 patients using 3% cidofovir twice daily showed response in 28 cases (80%), though this was in previously treatment-refractory cases. 6

• Contradictory evidence: One institutional review of 12 children showed only 25% complete clearance with 1-3% cidofovir, suggesting efficacy may be concentration and frequency-dependent. 4

Critical Safety Warnings

Renal toxicity concerns:

• Intravenous cidofovir causes nephrotoxicity, neutropenia, and metabolic acidosis. 1

• Topical cidofovir appears generally well-tolerated with mainly local irritation reported. 1, 2, 5

• One case report documented acute renal deterioration in a patient with pre-existing chronic renal failure during topical cidofovir treatment. 1

• Avoid in patients with renal impairment given the documented case of renal deterioration. 1

Other considerations:

• Local irritation is the most common side effect with topical use. 1

• Safety in pregnancy has not been established. 1

Recommended First-Line Treatments Instead

For cutaneous warts (hands/feet):

• Salicylic acid 15-40% after paring/debriding the wart. 7

• Cryotherapy with liquid nitrogen every 1-2 weeks. 7

For genital warts:

• Patient-applied: Podofilox 0.5% solution/gel (twice daily for 3 days, then 4 days off, up to 4 cycles) or imiquimod 5% cream (3 times weekly for up to 16 weeks). 1, 8, 9

• Provider-administered: Cryotherapy with liquid nitrogen (every 1-2 weeks) or TCA/BCA 80-90% (weekly). 1, 8, 9

Common Pitfalls to Avoid

• Do not use cidofovir as first-line therapy—it lacks sufficient evidence and guideline support for this role. 1

• Do not use in patients with renal disease without careful monitoring given the documented case of renal deterioration. 1

• Ensure proper compounding—cidofovir cream must be extemporaneously prepared from the parenteral formulation, as no commercial topical preparation exists. 1, 2

• Lower concentrations (1%) and less frequent dosing may be less effective than 3% applied twice daily based on comparative case series. 4, 6