(1) Except as otherwise provided in subsection (3) of this section, a health care provider may prescribe a prescription drug not on the preferred drug list to a medicaid recipient if (a) the prescription drug is medically necessary, (b)(i) the provider certifies that the preferred drug has not been therapeutically effective, or with reasonable certainty is not expected to be therapeutically effective, in treating the recipient's condition or (ii) the preferred drug causes or is reasonably expected to cause adverse or harmful reactions in the recipient, and (c) the department authorizes coverage for the prescription drug prior to the dispensing of the drug. The department shall respond to a prior authorization request no later than twenty-four hours after receiving such request.

(2) A health care provider may prescribe a prescription drug not on the preferred drug list to a medicaid recipient without prior authorization by the department or a managed care organization if the provider certifies that (a) the recipient is achieving therapeutic success with a course of antidepressant, antipsychotic, or anticonvulsant medication or medication for human immunodeficiency virus, multiple sclerosis, epilepsy, cancer, or immunosuppressant therapy or (b) the recipient has experienced a prior therapeutic failure with a medication.

(3) Neither the department nor a managed care organization shall require prior authorization for coverage for an antidepressant, antipsychotic, or anticonvulsant prescription drug that is deemed medically necessary by a patient's health care provider for a new or existing medicaid recipient if the medicaid recipient has prior prescription history for the antidepressant, antipsychotic, or anticonvulsant prescription drug within the immediately preceding ninety-day period. A prospective drug utilization review as described in section 38-2869 and applicable federal law for a prescription for an antidepressant, antipsychotic, or anticonvulsant prescription drug for a medicaid recipient with prior prescription history within the immediately preceding ninety-day period shall occur in order to ensure that the prescription for a medicaid recipient is appropriate and is not likely to result in adverse medical results. Use of a pharmaceutical sample is not considered prior prescription history.