(CBS Local) — Four lots of birth control pills are being voluntarily recalled because the packaging may be missing some tablets or may have an incorrect number of placebos, according to the U.S Food and Drug Administration.

The recall by Apotex Corp. is for Drospirenone and Ethinyl Estradiol Tablets, USP that were shipped nationwide. The tablets in the inner carton are normally arranged as 21 active yellow tablets followed by seven white placebo tablets.

“As a result of this packaging error, where a patient does not take a tablet due to a missing tablet or that a patient takes a placebo instead of an active tablet, loss of efficacy is possible due to variation in the dosage consumed,” the company said in its recall.

There have been no reports to the company of pregnancy or other adverse events, according to Apotex.

The following lots have been recalled: 7DY008A, 7DY009A, 7DY010A, and 7DY011A. The outer carton displays NDC No. 60505-4183-3 and NDC No. 60505-4183-1 on the inner carton. The expiration date is listed as August 2020.

If you have one of these impacted lots, you’re advised to contact your pharmacy.

“Individuals should not interrupt their therapy, use a non-hormonal method of birth control, contact their health care provider for medical advice and may return the impacted packages to their pharmacist,” the company said.

For more information click here, call 800-706-5575 or email Apotex.