(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).

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

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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