Your news story, 'Novartis criticised for switching heart drug brands', (page 6, 20 September) perpetuates the pharmaceutical industry's bad press.

Company representatives were said to have 'switched' medication to their own company's brands. If this is so, it raises issues about security in the practice. In my experience, a 'switch' cannot occur until all partners and the practice manager agree. Then practice staff carry out the switch, to maintain patient confidentiality.

I cannot believe a switch - which would have to be done on the practice computer - could be carried out without anyone in the practice being aware.

Consultancy companies offer this service as 'independent facilitators'. They have documents, put together by their lawyers, for clinicians and the practice manager to sign once a 'switch' has been agreed.

Every day, primary care organisations' pharmaceutical advisers also carry out 'switching'.

This, as in the case you cite, may be without any clinical evaluation and is simply a 'therapeutic class' for 'therapeutic class' switch.

WR Howlett Darlington