Background Cidofovir is a broad-spectrum antiviral agent with activity against several DNA viruses. In Portugal, it has to be imported but it has European Medicines Agency’s approval to treat cytomegalovirus retinitis in specific patient conditions.

A sixty-eight-year-old male patient, diagnosed with disseminated infection by molluscum contagiosum, with idiopathic acquired immunodeficiency CD4⁺ t-cells and pulmonary cryptococcosis treated three years ago, presented with severe erythroderma. He exhibited countless cutaneous lesions, characterised by severe pruritic millimetre papules which affected the majority of his body, impairing his life quality. The case was refractory to all on-label available therapies and has been prescribed topical cidofovir.

Purpose To share procedures followed after the prescription of a new off-label compounded drug: information research and development of specific procedures for this type of hazardous formulation.

Evaluation of treatment effectiveness, 3 months after the topical cidofovir application in the lower right member.

Material and methods Bibliographic research.

Prescription submission for approval of the ethics committee for health and clinical board of the hospital.

Elaboration of master formula sheet and parameterisation of labelling information.

Clinical evaluation and photographic register.

Results Numerous studies substantiate the prescription, which led to its approval by the referred hospital boards. Cidofovir 3% cream was compounded from injectable cidofovir (vistidine) and incorporated into commercially available fat cream (lipolium). Due to cidofovir’s mutagenic properties and its associated risk by exposure, this preparation was performed with proper protection equipment and using the luer-lock system (syringes and connectors). After 3 months of treatment, topical cidofovir proved to be effective, as the patient presented with a reduced number of lesions and less evidence of pruritus. He referred no symptoms of local irritation (the most reported adverse reaction).

Conclusion Off-label therapeutic options should be reserved only in specific cases. However, as long as there are no topical options available, compounding pharmacists can be essential in providing an effective and safe formulation. Operator’s safety should not be neglected, and the preparation must be carried out with appropriate precautions/protection equipment.

It should be noted that the success of this treatment required the commitment of a multidisciplinary team, with consequent improvement in patient’s life quality.

References and/or acknowledgements To be presented on poster.

No conflict of interest.