An unusual side effect of interferon alfa 2A: digital clubbing.

Interferon Alfa has been widely used to treat chronic hepatitis C virus infection. In this report, we present a case series of two patients referred to Sarwar Zuberi Liver Centre, Civil Hospital Karachi, who suffered from chronic hepatitis C. After getting detailed clinical examination and baseline work up prior to starting treatment, these patients were offered therapy with usual recommended dose of 3 million units of alpha-interferon subcutaneously thrice weekly. Both these patients developed clubbing of fingers during the course of treatment, one developing it during the 2nd month while the other during the 4th month. It was of grade II in one patient and of grade III in another and was bilateral in both the cases. Clubbing was not presented prior to start of treatment and no other secondary cause of clubbing was found in any of the case. These patients were not on any other drug that is known to interfere with interferon or can be associated with clubbing. No national or international data regarding such unusual side effect is available. Whether this effect is idiosyncratic or dose related and whether it is reversible or not after completion of treatment is yet to be established.