(a) Notwithstanding any provision of this chapter, except as provided in subdivision (b), a prescriber may dispense a dangerous drug, including a controlled substance, to an emergency room patient if all of the following apply:

1. (1) The hospital pharmacy is closed and there is no pharmacist available in the hospital.
2. (2) The dangerous drug is acquired by the hospital pharmacy.
3. (3) The dispensing information is recorded and provided to the pharmacy when the pharmacy reopens.
4. (4) The hospital pharmacy retains the dispensing information and, if the drug is a schedule II, schedule III, or schedule IV controlled substance, reports the dispensing information to the Department of Justice pursuant to Section 11165 of the Health and Safety Code.
5. (5) The prescriber determines that it is in the best interest of the patient that a particular drug regimen be immediately commenced or continued, and the prescriber reasonably believes that a pharmacy located outside the hospital is not available and accessible at the time of dispensing to the patient.
6. (6) The quantity of drugs dispensed to any patient pursuant to this section are limited to that amount necessary to maintain uninterrupted therapy during the period when pharmacy services outside the hospital are not readily available or accessible, but shall not exceed a 72-hour supply.
7. (7) The prescriber shall ensure that the label on the drug contains all the information required by Section 4076.

(b) Notwithstanding any provision of this chapter, including subdivision (a), a prescriber may dispense an unused portion of a dangerous drug acquired by the hospital pharmacy to an emergency room patient upon discharge under all of the following conditions:

1. (1) The dangerous drug is not a controlled substance.
2. (2) The dangerous drug has been ordered and administered to the emergency room patient.
3. (3) The dangerous drug was administered from single patient use multidose packaging and can be self-administered by the patient, including, but not limited to, an inhaler, eye drop, ear drop, nose drop or spray, topical product, or liquid product.
4. (4) Dispensing the unused portion of the dangerous drug is required to continue treatment of the emergency room patient.
5. (5) The prescriber shall ensure that the label on the drug contains all of the information required by Section 4076.