These reports, received within the UK between 1 April and 23 July 2009, mentioned 241 separate side effects. Most were mild and already recognised as linked with the anti-viral drug. They include ‘mild allergic and gastrointestinal events’, such as diarrhoea, nausea, stomach pain and vomiting.
There were five reports involving nine suspected adverse reactions to Relenza, another swine flu drug which is taken by inhalation and is less widely used. A suspected fatal reaction involving a patient who suffered liver failure after taking Tamiflu was later attributed to hepatitis.
The MHRA said previous reports from outside the UK had suggested a link between Tamiflu and liver failure but none had shown a causal link. A second report of a fatal reaction is being investigated.
'The balance of risks and benefits for Tamiflu and Relenza remains positive,' an MHRA spokesman said.
A spokesperson for Roche, the manufacturer of Tamiflu, said: ‘In clinical trials, Tamiflu (oseltamivir) was demonstrated to be a well-tolerated and effective medication for influenza prevention and treatment and has been used by more than 58 million people worldwide since 1999. It is also one of the few medicines that has a license for use by young children, who are a year old or under.’
The MHRA launched a new online reporting system earlier this month and GPs can now go online to report an suspected side effects to treatment with antivirals.
The agency said the new system was designed to make completing a report quick and easy for healthcare professionals and the public. The new online system is designed to assist the regulator in monitoring the safety of the swine flu antiviral medicines as their use increases during the pandemic.
More news from 27 July