US pharma giant Pfizer and a partnering distributor have been slapped with a record fine for hiking UK drug prices by 2,600% overnight.

In September 2012, the amount the National Health Service (NHS) was charged for 100mg packs of anti-epilepsy drug phenytoin sodium went from £2.83 to £67.50 ($3.56 to $84.98), according to the UK’s Competition and Markets Authority (CMA). As a result of the price increase, NHS expenditure on the drug increased from about £2 million ($2.52M) a year in 2012 to around £50 million ($62.95M) in 2013.

The CMA has ordered the two companies involved, the US pharma giant Pfizer and UK-based distributor Flynn Pharma, to pay record fines of £84.2 million ($106.01M) and £5.2 million ($6.55M) respectively, and to reduce their prices for phenytoin sodium. Both have said that they will be taking legal action to overturn the decision.