Family Doctor Association chairman Dr Peter Swinyard said this was one of a number of things GPs could do to 'cause the government discomfort' without seriously affecting patient care.
Practices could also refuse to take part in referral reduction schemes, or boycott commissioning groups, he suggested.
His comments came as talks between the BMA and other health unions continued over how doctors could show their support for the day of action.
Chairman of the BMA pensions committee Dr Andrew Dearden said the union would publish a Q&A factsheet in the coming weeks to answer members' questions on pensions.
Among the issues covered will be what form of action, industrial or otherwise, GPs can take to show their anger over pension reforms.
Dr Swinyard pointed out that his suggestions were not recommendations and that all decisions on industrial action would be taken by the BMA.
Some suggestions might be a breach of GPC guidance or even a breach of contract, Dr Swinyard warned.
But he said prescribing more expensive branded drugs to patients could prove an effective protest mechanism. 'We could blow budgets out of the sky within a month by prescribing much more expensive drugs, and using brand names,' Dr Swinyard said.
He argued that this would hit the government without affecting patient care. Other options could be not signing death certificates or refusing to write sick notes for government employees, he said.
Dr Swinyard said the BMA would not ask practices to take action unless it was 'absolutely necessary'.
Meanwhile, BMA Scotland recently called on members to express their views. Proposals published by the Scottish Public Pensions Agency mirrored contribution increases currently under consultation in England and Wales.