Pentoxifylline and severe acute respiratory syndrome (SARS): a drug to be considered

The recent outbreak of Severe Acute Respiratory Syndrome (SARS) as a new viral disease is causing a great concern for health authorities and general population. Very little is known about the infectious agent (a coronavirus) and its etiopathogeny, having no specific treatment yet. Proinflammatory cytokines released by stimulated macrophages in the alveoli could have a prominent role in pathogenesis of SARS. Current treatment of SARS with antiviral agents such as ribavirin and corticosteroids have not achieved very satisfactory results. Corticosteroids exert an antiinflammatory effect and are indicated for the treatment of respiratory distress, but, in the other hand, they exert an immunosuppressor effect on humoral and cellular arms of Immune System. Based on previous reports and on our own experience in HIV, we propose here pentoxifylline (PTX), a drug commonly used in vascular indications, as a possible treatment for SARS due to its interesting properties. PTX would feature a possible antiviral activity along with a well-known cytokine-modulating activity not as immunosuppressant as that of the corticoids, down-regulating proinflammatory cytokines but leaving functional the rest of the immune response. Other effects of PTX are discussed, as bronchodilation.

The antiinflammatory, antiviral, immunomodulatory and bronchodilatory effects of PTX, along with its low cost and toxicity, make it a promising drug to be considered for SARS treatment, alone or as an adjuvant therapy in combination with other drugs. The classical antiviral approach as single treatment for viral diseases should be reviewed in this occasion; immunomodulatory therapies could play an important role in SARS therapy.