PTCB Certified Pharmacy Technician (PTCE)Order Entry and ProcessingMedium
A patient calls the pharmacy asking about a prescription for 'Ambien 10 mg #30, Sig: 1 po hs prn insomnia.' The patient says they have been taking it nightly for 3 weeks and wonders why they are running out early. What is the most likely reason for the early refill request?
- AThe prescription was incorrectly filled with fewer tablets than ordered.
- BThe medication strength is too low, requiring extra doses.
- CThe patient is taking more than prescribed due to severe insomnia.
- DThe 'prn' instruction means it should only be taken as needed, not nightly.
Show answer & explanationAnswer & explanation
Correct answer: D. The 'prn' instruction means it should only be taken as needed, not nightly.
The 'prn' (pro re nata) instruction means 'as needed'. If the patient is taking it nightly instead of only when needed for insomnia, they would run out faster than if they were adhering to the 'as needed' directive.
Why the other options are wrong
- A. This is a dispensing error, which should be investigated, but the 'prn' instruction is a more likely cause for patient misunderstanding.
- B. The strength being too low would not directly cause an early refill unless the patient self-adjusted the dose, which relates back to understanding the 'prn' instruction.
- C. While possible, the 'prn' instruction is a more direct and common reason for running out early when misunderstood.
PRN Interpretation
Understanding that 'prn' (pro re nata) on a prescription means 'as needed,' indicating that the medication should only be taken when necessary, not on a fixed schedule.
- Common source of patient confusion.
- Affects medication adherence and supply duration.
- Requires patient education.
Memory trick: PRN Means 'As Needed,' Not a Daily Deed!