Pfizer and Flynn are accused of overcharging

Both Pfizer and Flynn Pharma are under investigation 
Both Pfizer and Flynn Pharma are under investigation 
ANDREW KELLY/REUTERS

Two large pharmaceutical companies are to be investigated for allegedly charging “excessive and unfair” prices for anti-epilepsy drugs used by more than 50,000 people in Britain.

Pfizer and Flynn Pharma are being investigated by the Competition and Markets Authority (CMA) for allegedly overcharging for phenytoin sodium, in a breach of UK and EU law.

The drug is made by Pfizer but marketed and sold to UK wholesalers and pharmacies by Flynn. It can prevent seizures in patients by helping to control electrical activity in the brain. It is typically given by injection after a seizure has started and can also be used to prevent or treat seizures caused by brain surgery or head injuries.

The competition watchdog said that, before 2012, when Pfizer made and