To investigate the effects and tolerance of amantadine in chronic hepatitis C patients.

Forty consecutive patients, with biopsy proven chronic active hepatitis, were treated with amantadine 200 mg daily in the morning for two months. Nineteen patients were previous non responders to alpha-interferon, nine patients experienced hepatitis relapse after interferon treatment, and twelve patients had never been treated with antiviral drugs. Complete blood count, liver and renal function tests were performed two months before, at baseline, end of therapy and two months after its completion.

None of the patients experienced significant side effects. Twenty-four patients (60%) showed a reduction of serum aminotransferase levels (twelve patients > 30% and twelve patients < 30% of their basal levels). The analysis of variance showed a significant reduction in aminotransferase levels at the end of treatment (F = 11, p < 0.0001). In four patients, aminotransferases returned to normal, but none of them cleared HCV-RNA. After the end of treatment, serum ALT returned to baseline values in all patients.

Amantadine is well tolerated in chronic hepatitis C patients. The time-relation between therapy and reduction of serum aminotransferase levels in 60% of patients suggests a potential anti-inflammatory activity of the drug without an effect on viraemia.