Influenza is a respiratory infection in which cough, runny nose, headache and fever are frequent manifestations. Most symptoms resolve without treatment within three to seven days. However, hospitalisation, pneumonia and even death may occur as rare complications of the illness, especially among children and the elderly. Pandemics are also a reason for concern. They occur when influenza spreads globally, infecting 20% to 40% of the world's population, resulting in as many as 10 million deaths.
Oseltamivir (also known as Tamiflu) is currently used for patients with influenza on the recommendation of the World Health Organization (WHO). In previous pandemics, the virus was susceptible to amantadine and rimantadine. So, if they are safe and if the circulating strain proves to be susceptible to these drugs, they could be a less expensive alternative in the management of influenza. This reinforces the importance of conducting reviews on a variety of drugs for the treatment and prevention of influenza. We conducted a review of trials in children and the elderly groups. We selected 12 trials on 1586 children and adolescents and 908 elderly were selected.
Amantadine can prevent influenza in children but it would be necessary to use the drug in up to 17 children during a 14- to 18-week period to prevent one case of influenza. There was no evidence of adverse effects of amantadine in children. We could not reach a conclusion on its use or adverse effects in the elderly, as we did not identify any amantadine trials in the elderly that met our inclusion criteria.
The only observed benefit of rimantadine was in the abatement of fever by day three of treatment in children.
Although it is not the objective of this review, it is possible to speculate if rimantadine can be prescribed in selected cases, such as in children with underlying medical conditions in which fever may lead to complications, or may impair treatment or control of diseases such as diabetes, cardiopulmonary illness and chronic anaemia, such as sickle cell disease. New trials should answer this issue.
Due to the small number of studies, we could not reach a definitive conclusion on the safety of amantadine or the effectiveness of rimantadine on preventing influenza in both age groups.