(CBS) — There is a recall out for certain thyroid medications because they may not be strong enough to be effective. A recall notice on the FDA’s website from Acella Pharmaceuticals states that one lot of 15-mg and one lot of 120-mg NP Thyroid, Thyroid Tablets, USP were found to be “sub potent.”

The medications used to treat an underactive thyroid come in 100-count bottles. So far, four patients have reported adverse effects while taking the recalled drugs.

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The recalled prescription bottles have expiration dates of either October 2020 (Lot # M327E19-1) or November 2020 (M328F19-3).

Anyone who is currently taking the recalled medication should contact their doctor before they stop taking it.

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An underactive thyroid can cause symptoms like swelling, depression and slow heart rate. It also poses a risk to pregnant women and their fetuses.

Read the full recall notice here.

Earlier this month RLC Labs recalled 483 lots of its Nature-Throid and WP Thyroid for sub-potency.

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