OTTAWA -- Health Canada says Apotex Inc. will be recalling 11 additional lots of Alysena-28 birth control pills as a precautionary measure.

Apotex is making the additional recall while it investigates why one lot -- LF01899A -- of the product contained packages with extra placebo pills in place of active pills.

Packages of Alysena-28 should have three rows of the pink active pills and only one row of white placebo pills.

Canadians using this product should use a non-hormonal method of birth control, contact their health care provider for medical advice and return unopened packages to their pharmacist.

Alysena-21, which is manufactured at the same facility, is not part of the current recall as these packages don't normally include a row of the placebo pills.

However, because the product is made in the same facility, Health Canada and Apotex are working together to verify this product as well.

In the meantime, Canadians are encouraged to check to make sure their packages of Alysena-21 contain three rows of pink pills.

Consumers are also strongly encouraged to report any medical problems associated with the use of Alysena-28 or Alysena-21 to Health Canada.

The specific lots involved in the new recall are: LF01901A, LF01980A, LF02037A, LF01900A, LF01982A, LF01981A, LF02026A, LF01898A, LF02036A, LF01894B, and LF01979A.