Chloroquine diphosphate: a risk factor for herpes zoster in patients with dermatomyositis/polymyositis

da Cunha, Gilmara Franco; de Souza, Fernando Henrique Carlos; Levy-Neto, Maurício; Shinjo, Samuel Katsuyuki

However, patients using chloroquine diphosphate had a fivefold greater risk of developing HZ compared to patients not receiving chloroquine diphosphate treatment. Chloroquine diphosphate and its analogue, hydroxychloroquine, are used to treat various rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, dermatomyositis, Sjö gren's syndrome, chronic juvenile arthritis and psoriatic arthritis; these drugs offer clinical benefits with acceptable safety profiles (26) (27) (28) (29) . Further, these drugs have also been used to treat inflammatory myopathies, particularly for the cutaneous symptoms of DM (30) (31) (32) (33) (34) . Chloroquine might also have antiviral activity (35) . As a lysosomotropic weak base, it impairs the replication of some viruses by reducing the efficiency of endosome-mediated virus entry or by inhibiting low-pH-dependent proteases in trans-Golgi vesicles (35) . Its antiviral activity against the human immunodeficiency virus (36) and the SARS coronavirus has also been demonstrated (37, 38) . However, chloroquine has also been shown to increase symptom severity and mortality (e.g., following Semliki Forest virus and encephalomyocarditis virus infection, as well as increasing viral titers in various organs) (39) . Our results clearly showed that chloroquine was a risk factor for HZ development in subjects with DM/PM, independent of disease status, therapy and demographic features.