• Lupin Pharmaceuticals announced a voluntary recall of two batches of Tydemy birth control pills on July 29.
• The pills tested low for ascorbic acid, which could reduce their effectiveness and result in unwanted pregnancy, the FDA said.
• Lupin advised patients to continue taking their medication and immediately consult with their doctor about an alternative form of contraception.

The U.S. Food and Drug Administration has warned that some Tydemy birth control pills may not be effective, several days after the manufacturer recalled two batches of the medication that were distributed in the U.S.

The FDA said the pills in question could result in unexpected pregnancy. The agency has not received any reports of adverse events related to Tydemy so far.

The manufacturer, Lupin Pharmaceuticals, announced a voluntary recall of two batches of Tydemy on July 29. The pills in those batches were distributed in the U.S. between June 3, 2022, and May 31, 2023.

Lupin, in a statement last week, said it recalled the batches because pills in one batch tested low for ascorbic acid and "high for a known impurity." The company said a significant reduction in ascorbic acid could affect the product's effectiveness.

Lupin said it is notifying wholesalers, distributors, drug chains and supermarkets of the problem and is working to get the affected pills off store shelves. Any store, distributor or wholesaler that has the affected pills in stock should immediately stop distributing them, the company said.

The batches of Tydemy that may not be effective come from lot numbers L200183 and L201560.

Lupin advised patients to continue taking their medication and immediately consult with their doctor about an alternative form of contraception.