Some drugs are identified as having a narrow therapeutic index (NTI) by the Food & Drug Administration (FDA). With NTI drugs, small changes in the dosage could cause toxic results.

Patients taking NTI drugs require constant monitoring so that the level of medication can be adjusted to assure uniform and safe results. Members will not be required to pay the difference in cost between brand and generic for drugs that are classified as NTI medications.

NTI drugs are identified in the Wellmark Drug List.