IntroductIonChronic hepatitis C represents a major public health problem worldwide. The estimated average global prevalence is close to 3% (ranging from 0.1% to 5% in different countries). Therefore, there are about 175 million carriers of hepatitis C virus (HCV) worldwide (24) . Approximately 30% of infected patients develop cirrhosis in 20-30 years and 1%-4% are considered at high risk of developing hepatocellular carcinoma (23) . The chronicity of hepatitis C is characterized by persistent HCV for 6 months. Prospective studies show that 60% to 85% of these infections progress to chronicity (15,24) . AbstrAct -Context -Pharmacovigilance studies aim to detect, assess, understand and prevent risks of adverse effects of medications or any other possible drug related problem. Alpha interferon is being produced by Bio-Manguinhos/Fiocruz, Rio de Janeiro, RJ, Brazil and used in the treatment of chronic hepatitis C at Brazilian National Health System. Objective -To study the safety profile and effectiveness of alpha interferon in a sample of Brazilian patients with chronic hepatitis C genotypes 2 and 3, in Porto Alegre, RS, Brazil. Method -We followed a cohort of chronic hepatitis C genotypes 2 and 3 patients treated with alpha interferon plus ribavirin in a specialized outpatient clinic in southern Brazil. Adverse events were collected and classified according to severity in monthly structured interviews. To measure effectiveness, hepatitis C viral load was evaluated before, at the end and 24 weeks after the treatment. Results -We followed 141 patients during the study period, of which 52.5% were female with mean age of 52 years. The most frequent adverse events were fatigue (84%), headache (79%) and myalgia (75%). There were 13 treatment interruptions due to adverse events, 9 of those considered serious adverse events. Virological response at end of treatment was 54.6% and after 24 weeks 39.7%, considering all patients who started treatment. Conclusion -The product produced by Bio-Manguinhos has similar efficacy and adverse event and sustained virological response profiles comparable to those found in the literature. This is the first study of pharmacovigilance performed with the Brazilian product. These data will be useful for planning and management of this disease in Brazil. HEADINGs -Hepatitis C, chronic. Interferon alpha. Ribavirin. Adverse drug reaction reporting systems.The authors declare no conflicts of interest. Study carried out at

Despite the extensive research on the pharmacology of L-arginine, there are only few data on its antithrombotic properties. We studied the effect of oral L-arginine administration in a model of arterial thrombosis in rabbits divided into three groups: group 1, group without intervention; group 2, control group, treated with normal diet and submitted to the thrombosis-triggering protocol; group 3, treated for 2 weeks with L-arginine (2.25%) prior the protocol. L-Arginine did not alter platelet aggregation nor coagulation parameters but reduced vascular activities of both ADPase (49.1 +/- 8.5 versus 28.9 +/- 8.3 versus 18.8 +/- 10.3 nmoles inorganic phosphate/min per mg protein; mean +/- SD; group 1 versus group 2 versus group 3, respectively; ANOVA F = 19.21; P < 0.0001) and ATPase (97.8 +/- 15.8 versus 52.1 +/- 11.6 versus 31.9 +/- 16.3 nmoles inorganic phosphate/min per mg protein; mean +/- SD; group 1 versus group 2 versus group 3, respectively; ANOVA, F = 34.65; P < 0.0001). L-Arginine did not reduce the thrombi area (17.1 mm, 9.02 and 48.07, versus 27.04 mm, 25.4 and 70.39, median, percentile 25 and 75 respectively, P = 0.079; group 2 versus group 3, respectively). In conclusion, oral L-arginine administration did not inhibit thrombosis, and, conversely, it significantly reduced the arterial wall ADPase and ATPase activities. This effect may limit its antithrombotic properties.