United States
Hong KongSchedule III to V refills
A prescription for a Schedule III or IV controlled substance may not be filled or refilled more than six months after the date it was issued, nor refilled more than five times, under 21 CFR 1306.22.
Two numbers, and the exam question is almost always about which one runs out first.
The rule
No filling or refilling more than six months after the date the prescription was issued, and no more than five refills. Both conditions are in 21 CFR 1306.22 and both apply.
A patient who uses all five refills in four months is done at four months. A patient with two refills left at the six-month mark loses them. The exam sets up exactly these situations, and the answer is never the more generous of the two limits.
Counting the fills
Five refills means six dispensings in total: the original fill plus five. Reading "five refills" as five total dispensings is the commonest arithmetic slip in this area.
The date that matters
Six months from the date the prescription was issued, not from the date it was first filled. A prescription presented two months after it was written has four months of life left, not six.
Schedule V
Schedule V is less restricted than III and IV, and some Schedule V products are subject to separate rules on retail sale. Where a question concerns a Schedule V product sold without a prescription, it is testing the listed-chemical and retail-sale rules rather than the refill rules.
Contrast with Schedule II
Schedule II has no refills at all. The exam frequently pairs the two, offering the III and IV limits as a distractor on a Schedule II fact pattern.
Check the schedule before you reach for the numbers. That is the whole defense.
Common questions
How many refills are allowed for Schedule III and IV?
Up to five, and not more than six months after the prescription was issued.
Which limit applies if they conflict?
Whichever arrives first. Both conditions bind.
How many total dispensings is five refills?
Six - the original fill plus five refills.
Does the six months run from the fill date?
No, from the date the prescription was issued.
What is the common trap?
Applying these limits to a Schedule II prescription, which has no refills at all.