10.— (1) Subsection (2) shall apply where a pharmacist who is working in a retail pharmacy business is presented with a prescription, by the patient for whom the prescription was issued or a person acting on behalf of the patient, for a branded interchangeable medicinal product which is not the subject of a clinical exemption and, at the time the prescription is presented, the retail pharmacy business does not currently have in stock the branded product but does have in stock 2 or more substitute medicinal products each of which the pharmacist reasonably believes is of equal or lower cost to the Executive (as specified in the Reimbursement List) or the patient, as the case may be, than the branded product.

(2) The pharmacist shall offer the patient, or the person acting on behalf of the patient, as the case may be, the opportunity to agree to the pharmacist substituting the branded product with one of the substitute medicinal products chosen by the patient, or the person acting on behalf of the patient, as the case may be—

(a) after the pharmacist has informed the patient, or the person acting on behalf of the patient, as the case may be, that the retail pharmacy business does not currently have in stock the branded product, and

(b) with the pharmacist offering that opportunity, unless the patient, or the person acting on behalf of the patient, declines any substitution, by starting with the substitute medicinal product which is of the lowest cost to the Executive (as specified in the Reimbursement List) or the patient, as the case may be, and, if substitution is not agreed at that stage, proceeding to the substitute medicinal product which is of the next lowest cost to the Executive (as specified in the Reimbursement List) or the patient, as the case may be, and so on until substitution has been agreed or each of those substitute medicinal products has been made the subject of that opportunity without substitution being agreed, whichever first occurs.

(3) Where the patient, or the person acting on behalf of the patient, to whom an offer referred to in subsection (2) is made by a pharmacist agrees to the substitution the subject of the offer, the pharmacist shall effect the substitution.