Is there a law that prevents controlled substance services for 90 days?

There is no specific law that prohibits a pharmacist from dispensing more than 30 days' worth of a controlled substance at a time. The pharmacist must follow the prescription provided by the doctor, whether it specifies a certain quantity to be dispensed or a standard dosage to be taken daily. The pharmacist also has the professional judgment to dispense a lesser quantity of medication if deemed appropriate.