UPDATE 1-J&J's Ionsys drug safety questioned by EU agency

* Marketing authorisation lifted due to safety concerns

* EMEA says no reports of serious adverse events so far

* Safety worries centre on corrosion in delivery system

* Shares drop 1.8 percent in U.S.

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LONDON, Nov 20 (Reuters) - Approval for Johnson & Johnson (JNJ.N) to sell its pain medicine Ionsys in Europe should be suspended because of a defect with the drug's delivery system that could lead to overdose, the European Medicines Agency (EMEA) said on Thursday.

The stock fell 1.8 percent to $57.03, helping to pull the Dow Jones Pharmaceuticals Index .DJUSPR down 0.26 percent after the European Medicines Agency's announcement.

Recommendations by the agency's Committee for Medicinal Products for Human Use (CHMP) are normally endorsed by the European Commission.

The agency said a defect with the delivery system of the medicine indicated to ease post-operative pain could lead to patients being overdosed. The drug is marketed in Europe by J&J unit Janssen-Cilag.

Janssen-Cilag told the agency that it had detected corrosion of a component in the delivery system in batch of the drug, which could trigger self activation of the system, causing an overdose.

An overdose could cause respiratory depression, a life-threatening complication.

The company said it has not been able to identify the cause of the defect, or pick it up with its testing system.

However there have been no reports of serious adverse events associated with the malfunction of the device -- in particular related to self-activation of the system -- or of an overdose as a result, the agency added.

(Reporting by Ben Deighton; editing by Michael Kahn and Elaine Hardcastle)