According to the a letter Johnson & Johnson’s (Stock Quote: JNJ)McNeil Consumer Healthcare sent to doctors and health officials, one product, a one-milligram grape version of children's Zyrtec, was inadvertently not listed in the original recall due to a clerical error.  

The product was added to the list five days later. The letter, obtained by The Wall Street Journal, also revealed that McNeil told its sales staff to inform retailers they should remove the product from their shelves. No separate recall was issued.  

The company also said in the letter that tests from samples of the recalled Tylenol products revealed that some of the medications contained up to 24% more of the active ingredient than listed.

The disclosure comes just two days after the FDA announced its company-wide investigation of McNeil. The initial recall involved about 40 versions of children’s Tylenol, Motrin, Zyrtec and Benadryl products.

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