Missouri Revised Statutes Title XII. Public Health and Welfare § 195.080. Excepted substances--prescription or dispensing limitation on amount of supply, exception--may be increased by physician, procedure

1. Except as otherwise provided in this chapter and chapter 579, this chapter and chapter 579 shall not apply to the following cases:  prescribing, administering, dispensing or selling at retail of liniments, ointments, and other preparations that are susceptible of external use only and that contain controlled substances in such combinations of drugs as to prevent the drugs from being readily extracted from such liniments, ointments, or preparations, except that this chapter and chapter 579 shall apply to all liniments, ointments, and other preparations that contain coca leaves in any quantity or combination.

2. The quantity of Schedule II controlled substances prescribed or dispensed at any one time shall be limited to a thirty-day supply.  The quantity of Schedule III, IV or V controlled substances prescribed or dispensed at any one time shall be limited to a ninety-day supply and shall be prescribed and dispensed in compliance with the general provisions of this chapter and chapter 579.  The supply limitations provided in this subsection may be increased up to three months if the physician describes on the prescription form or indicates via telephone, fax, or electronic communication to the pharmacy to be entered on or attached to the prescription form the medical reason for requiring the larger supply.  The supply limitations provided in this subsection shall not apply if:

3. The partial filling of a prescription for a Schedule II substance is permissible as defined by regulation by the department of health and senior services.