Effect of interferon therapy on heart rate and sympathetic nervous system.

We investigated the hypothesis that interferon-induced hyperadrenergic state causes cardiovascular events. Thirteen patients with chronic hepatitis C who were scheduled to undergo interferon therapy were randomly selected for this study. Heart rate was monitored and urinary levels of catecholamines were measured before, on the 1st day, and after 1 week and 4 weeks of treatment. On the 1st day, 24-hr average heart rate and hourly average heart rate were significantly higher than those before treatment, although they returned to baseline levels after 1 week and 4 weeks. However, urinary levels of cathecholamines did not change significantly on the 1st day of interferon therapy. Although the direct evidence that interferon stimulates sympathetic nervous system could not be obtained, interferon elicited tachycardic response and may have increased the risk of arrhythmias of the 1st day of the treatment.