GSK's anti-depressant Paxil is one of the two drugs seized

In a statement, the FDA said the two drugs affected were diabetes tablets Avandamet and the slow-release anti-depressant Paxil CR.

The FDA said the two products failed to meet standards for safety, strength, quality and purity.

Yet it added that it did not believe they posed a health hazard.

Patients who are taking either medication have been advised to continue to do so, but also talk to their doctor about the possibility of using alternative products until the manufacturing problems are corrected.

Shares down

The FDA said that the Paxil CR tablets could split apart, leaving a person with part of a tablet that did not contain the active ingredient.

And the Avandamet tablets did not have an accurate dose of their active ingredient, it said.

"FDA and the Department of Justice will not allow drug manufacturers to ignore our high public health standards for drug manufacturing," said John Taylor, FDA associate commissioner for regulatory affairs.

Glaxo said it was working to resolve manufacturing problems as quickly as possible.

Yet it added that both drugs would be in short supply in the United States in the short term. UK-based Glaxo saw its shares closed down 2.2% in London following the FDA announcement.