The European Commission has released new amendments to the EU's recent pharmacovigilance legislation after it said it was made aware of several potential loopholes through which dangerous products could escape monitoring.

In a 4 October statement, the EC said the changes were mostly done as a result of a recent scandal involving the anti-diabetes drug Mediator, which was removed in most countries but remained on the market in France. It has been implicated in thousands of adverse events and hundreds of deaths, and EU officials said it, "Revealed some weaknesses in the EU system concerning pharmacovigilance."

In response to stress testing, EC said it had released a handful of new procedures aimed at closing down potential loopholes in the legislation.

Sponsors of marketed products will meanwhile be required to justify all withdrawals of a product from the market, as well as suspensions or non-renewals of marketing authorizations.

"[The new rules] will lead to strengthened monitoring of additional categories of medicinal products. Patients and health professionals will recognize these medicines thanks to a standard black symbol, and an explanatory statement about the product's characteristics," explained the EC in a statement. "That statement will encourage all users to report suspected adverse reactions to these medicinal products."

In addition to requiring additional monitoring and notification procedures, the EC said the new amendments will allow for automatic assessments of pharmacovigilance issues at the EU level if serious safety concerns are raised. In addition, sponsors required to conduct post-approval safety studies will also have their products included in a list of medicines which the EC said will be subject to increased monitoring.

The new rules are scheduled to come into full effect by October 2013.