MADISON, N.J. (CBSDFW.COM/AP) — Allergan is voluntarily recalling packs of its birth control pills in the U.S. because of a packaging error with placebos, increasing the possibility of unintended pregnancy.

The company says four placebo pills were placed out of order in the Taytulla packs. Allergan says the first four days of therapy had four non-hormonal placebo capsules instead of active capsules.

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The physician sample packs were intended to have 24 active pink pills, followed by four inactive maroon capsules, taken daily for 28 days.

Part of the announcement posted on the Food and Drug Administration website said, “The reversing of the order may not be apparent to either new users or previous users of the product, increasing the likelihood of taking the capsules out of order. If patients have concerns regarding the possibility of an unintended pregnancy they should consult their physician.”

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The recall involves lot 5620706, which expires in May 2019.

Allergan said it was notifying consumers by letter of the packaging error and is arranging for the return of all the recalled sample pack products. Consumers with questions about the recall are being asked to contact Allergan at 800-678-1605, Monday through Friday.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)