Final answer:
C III - C V controlled substance prescriptions are valid for 180 days from the date of issuance, with up to five refills allowed for Schedule III and IV substances within that period.
Step-by-step explanation:
The validity period for prescriptions of controlled substances classified under Schedule III (C III) to Schedule V (C V) is 180 days from the date of issuance. This means after a prescription for a C III - C V substance is written, it can be filled within that 180-day timeframe. It is important to note that these prescriptions also have a limit on the number of refills within that time; no more than five refills are allowed on Schedule III and IV controlled substances within six months. Prescriptions cannot be refilled for Schedule V drugs unless the prescription otherwise permits.