Background and Importance Epidermolysis bullosa (EB) is a group of rare genetic diseases characterised by fragility of the skin, resulting in painful and itchy blisters. Although there is no curative treatment for EB, some measures may help to relieve symptoms.

Aim and Objectives To describe a clinical case of a patient with EB and evaluate the effectiveness and tolerance of a ketamine and amitriptyline formula.

To develop and validate a topical gel of ketamine and amitriptyline.

Material and Methods A 29-year-old woman with dystrophic pruritic EB in her lower extremities since she was 3 years old. She was previously treated with methotrexate, oral and topical corticosteroids and cyclosporine. Due to the adverse effects of oral therapy, Dermatology requested a topical formulation of ketamine and amitriptyline.

A literature search on the efficacy, safety and composition of the formula was conducted. A 1% ketamine with 1% amitriptyline gel was developed and the physical and organoleptic characteristics were analysed at 0, 14, 28 and 42 days. Clinical follow-up was carried out during Pharmacy and Dermatology visits to assess the response to the treatment.

Results The literature reported several cases of ketamine and amitriptyline gel (KAG) at different concentrations for treating chronic pruritus and EB. The off-label use was approved by the medicines-in-special-situations local committee.

Procedure for 400 grams: In phase 1, dissolve 0.6g of sodium methylparaben in 280mL of water and heat it up to 60–70°C. In phase 2, heat 4g of amitriptyline and 40g of glycerol in a second beaker. Add gradually 4g of carboxymethylcellulose at phase 2 until a homogeneous suspension is obtained. Mix both phases at 70°C and stir vigorously until a whitish gel is obtained. After cooling, add 80g of ketamine vial (50mg/mL) and homogenise it. The gel is homogeneous, fluid, whitish, odourless and has good extensibility.

From the treatment’s beginning, the patient showed improvement of the pruritus, good tolerance and satisfaction. After 6 weeks, she was ongoing with KAG and applies it every 3 hours instead.

Conclusion and Relevance In our patient, topical KAG is an effective and safe alternative to consider in the EB treatment. The medium long-term effects will be assessed through follow-up. During the studied period, the formula developed maintains stability.

Conflict of Interest No conflict of interest.