We may add or remove drugs from our formulary during the year. We will notify you of a negative formulary change at least 60 days before the date that the change becomes effective through a formulary change notice. A negative formulary change occurs when we remove a drug from our formulary or add prior authorization, quantity limit or step therapy restrictions on a drug. It also occurs when we move a drug to a higher cost-sharing tier. If the Food and Drug Administration deems a drug on our formulary to be unsafe or the drug's manufacturer removes the drug from the market, however, we will immediately remove the drug from our formulary.