Clinical Trials: Adult Treatment Studies: In phase III clinical studies in the treatment of influenza, the most frequently reported adverse events were nausea and vomiting. These events were transient and generally occurred with first dosing. These events did not lead to patient discontinuation of study drug in the vast majority of instances. Those events with an incidence of ≥ 1 % and which were reported more frequently in patients taking osetamivir compared with placebo, irrespective of causality, were nausea, vomiting, abdominal pain and headache. Other events reported are diarrhoea, bronchitis, dizziness and insomnia.
Adult Prophylaxis studies: Adverse events were qualitatively very similar to those seen in the treatment studies, despite a longer duration of dosing. Events reported more frequently in subjects receiving oseltamivir compared to subjects receiving placebo in prophylaxis studies, and more commonly than in treatment studies, were aches and pains, rhinorrhea, dyspepsia and upper respiratory tract infections. However, the difference in incidence between oseltamivir and placebo for these events was less than 1%. There were no clinically relevant differences in the safety profile of the elderly subjects, who received oseltamivir or placebo, compared with the younger population.
Paediatric treatment studies: Adverse events occurring in > 1% of children receiving oseltamivir are vomiting, diarrhoea, otitis media, abdominal pain, asthma, nausea, epistaxis, pneumonia, ear disorder, sinusitis, bronchitis, conjunctivitis, dermatitis, lymphadenopathy and tymphanic membrane disorder. The most frequently reported adverse event was vomiting. These events generally occurred once, resolved despite continued dosing and did not cause discontinuation of treatment in the vast majority of cases.
Paediatric Prophylaxis: Gastrointestinal events were the most frequent, particularly vomiting.
Post-Marketing: Skin and subcutaneous tissue disorder: rare cases of hypersensitivity reactions such as allergic skin reactions including dermatitis, rash, eczema, urticaria, and very rare cases of erythema multiforme and Stevens-Johnson-Syndrome and toxic epidermal necrolysis are reported. Also, allergy, anaphylactic/anaphylactoid reactions and face edema are reported rarely.
Liver and biliary system disorder: very rare reports of hepatitis and elevated liver enzymes have been reported in patients with influenza like illness receiving oseltamivir.
Psychiatric disorders/Nervous system disorders: Convulsion and delirium (including symptoms such as altered level of consciousness, confusion, abnormal behaviour, delusions, hallucinations, agitation, anxiety, nightmares) have been reported during oseltamivir administration in patients with influenza. predominately in children and adolescents. In rare cases, these events resulted in accidental injury. The contribution of oseltamivir to those events is unknown. Such neuropsychiatric events have also been reported in patients with influenza who were not taking oseltamivir.
Gastro-intestinal disorders: In rare cases gastro-intestinal bleedings were observed after the use of oseltamivir. In particular, haemorrhagic colitis was reported that subsided when the course of influenza abated or treatment with oseltamivir was interrupted.