(a) during emergency medical treatment unrelated to abuse of controlled substances;

(b) who is a bona fide patient suffering from an incurable and fatal disease such as cancer or advanced tuberculosis;

(c) who is aged, infirm, or suffering from serious injury or illness and the withdrawal from controlled substances would endanger the life or impede or inhibit the recovery of such person. 2. Controlled substances may be ordered for use by an addict or habitual user by a practitioner and administered by a practitioner or registered nurse to relieve acute withdrawal symptoms. 3. Methadone, or such other controlled substance designated by the commissioner as appropriate for such use, may be ordered for use of an addict by a practitioner and dispensed or administered by a practitioner or his designated agent as interim treatment for an addict on a waiting list for admission to an authorized maintenance program. 4. Methadone, or such other controlled substance designated by the commissioner as appropriate for such use, may be administered to an addict by a practitioner or by his designated agent acting under the direction and supervision of a practitioner, as part of a regime designed and intended to withdraw a patient from addiction to controlled substances. 5. Methadone, or such other controlled substance designated by the commissioner as appropriate for such use, may be administered to an addict by a practitioner or by his designated agent acting under the direction and supervision of a practitioner, as part of a substance abuse or chemical dependence program approved pursuant to article twenty-three or thirty-two of the mental hygiene law.