(1) The formulary is considered to be a part of the Montana Guidelines established by the department. 

(2) A medical provider is expected to write a prescription for medication in accordance with the Montana Guidelines, as adopted by ARM 24.29.1611, and in accordance with the formulary adopted by ARM 24.29.1616.

(3) Because the formulary is part of the Montana Guidelines, medical providers are required to prescribe in accordance with the provisions of the formulary unless the provider can sufficiently articulate sound medical reasoning to vary from the formulary.

(4) Insurers shall pay for medications that are prescribed in a manner consistent with the formulary, subject to the medical provider furnishing documentation as required by ARM 24.29.1621. Payments for medications are subject to the provisions of 39-71-727, MCA.

(5) Pursuant to the formulary, prior authorization for an injury appropriate medication is not required as follows:

(a) the medication is listed as "Y" on the formulary; or

(b) the medication is listed as "N" on the formulary, and the prescription is:

(i) written within seven days of the occurrence of the workplace injury; and

(ii) limited to a maximum of a seven-day supply of the medication.

(6) Pursuant to the formulary, prior authorization for a medication is required as follows:

(a) except as provided by (5)(b), the medication is listed as "N" on the formulary;

(b) the medication is not listed on the formulary;

(c) the medication is experimental or investigational; or

(d) the medication is a compound, even if all the components of the compound are listed as "Y" medications on the formulary.

(7) The prior authorization process described in ARM 24.29.1621 applies to formulary matters, except that:

(a) the insurer shall respond within three business days of the receipt of a request for prior authorization being made to the insurer or the insurer's designee, by either approving or denying the request; and

(b) if the insurer fails to respond within three business days to a request for prior authorization, the prescription is deemed to be approved. An approval for a prescription medication made due to the lack of a timely response by the insurer does not apply to any refill that may be ordered.

(8) An insurer may delegate prior authorization decisions pertaining to the formulary to a PBM or other agent with which it contracts. An insurer has the legal responsibility for the decisions made by the PBM on behalf of the insurer.

(9) The delegation by an insurer of prior authorization decisions pertaining to the formulary to a PBM or other agent does not, in and of itself, violate the requirement of 39-71-107, MCA, that all claims be examined by a claims examiner in Montana.