TABLE 2.

Opportunities to Address Concerns Regarding Therapeutic Interchange

Concern	Potential Policy Response
Narrow therapeutic index drugs can pose patient safety issues, as a small change in blood concentration can lead to a major difference in patient response.	Policy can expressly prohibit interchange for narrow therapeutic index drugs. Idaho law states: “Nothing in this section shall apply to…narrow therapeutic index drugs.” Idaho law further defined narrow therapeutic index drugs as “a drug where a small difference in dose or blood concentration may lead to serious therapeutic failures or adverse drug reactions.”
Pharmacists should have a conversation with the physician about which medication they will dispense before dispensing it.	Policy can require a physician to opt-in on the original prescription. This proactive prescriber opt-in, which occurs before dispensing, retains prescriber autonomy but removes the hassle of the pharmacist having to contact the prescriber for common sense interchanges when the patient’s health plan has a different preferred drug in the same therapeutic class.
Physicians may be confused about how therapeutic interchange differs from brand-generic substitution and may not be sure what they are opting-in to.	Brand-generic substitution has become a default that prescribers can opt-out of. In 2016, nearly 3.9 billion generic prescriptions were dispensed in the United States.27 Requiring a prescriber to opt-in to therapeutic interchange creates a suitable distinction between the 2 concepts.