Skip to main content

Box 9 Prescribing guidelines for pegylated interferon alfa-2a

From: French guidelines for the etiological workup of eosinophilia and the management of hypereosinophilic syndromes

Pegylated interferon alfa-2a is administered by weekly subcutaneous injections. In HES, common practice is to start with low doses (e.g., 45 μg per week, less than those used for myeloid neoplasms or viral hepatitis) to promote tolerability and long-term adherence. Combination with prophylactic administration of paracetamol (1 g every 8 hours for 24–48 hours) should be offered to reduce flu-like symptoms that can sometimes be observed after injection.

Pegylated interferon alfa-2a is contraindicated in children under 3 years of age, in case of documented hypersensitivity to benzyl alcohol, severe decompensated liver failure, thrombocytopenia < 100 × 109/L or progressive autoimmune disease (particularly systemic lupus erythematosus, dermatomyositis, other diseases mediated by interferon pathways and autoimmune hepatitis). Overall, if there is a history of preexisting autoimmune disease, the benefit/risk ratio of treatment with pegylated interferon alfa-2a should be weighed on a case-by-case basis. In patients with a history of mood and/or personality disorders, a psychiatrist should be consulted prior to initiation of treatment (and monitoring increased if necessary), as this drug may induce mood disorders.

In addition, regular laboratory monitoring (including CBC, serum electrolytes, creatinine, transaminases, TSH) is recommended. In the event of cytopenia, the intervals between injections of pegylated interferon alfa-2a may be increased and/or the dosages reduced.