“So what steps can a regulator take when it has established that there is a problem? In very extreme cases it can remove a drug from the market (although in the US, technically drugs usually stay on the market, with the FDA advising against their use). More commonly it will issue a warning to doctors through one of its drug safety updates, a ‘Dear Doctor’ letter, or by changing the ‘label’ (confusingly, in reality, a leaflet) that comes with the drug. Drug-safety updates are sent to most doctors, though it’s not entirely clear whether they are widely read. But, amazingly, when a regulator decides to notify doctors about a side effect, the drug company can contest this, and delay the notice being sent out for months, or even years.”