q4h
Medical abbreviation · Prescription
| Stands for | Every 4 hours |
|---|---|
| Categories | Medical |
q4h stands for Every 4 hours, a prescription abbreviation.
Interval dosing that delivers six doses in 24 hours, used for short-acting analgesics, nebulized bronchodilators and frequent vital signs. Doses are timed four hours apart around the clock unless the order is PRN.
Example: Oxycodone 5 mg PO q4h PRN moderate pain (4-6/10).
Usage notes
Written with or without capitals and periods (Q4H, q 4 hr, q.4.h.). Classical Latin is "quaque quarta hora". When paired with PRN, q4h sets the minimum gap between doses, not a requirement to give them. The UK BNF lists an older Latin form, "q.q.h." (quarta quaque hora), for the same interval.
Related abbreviations
More prescription abbreviations
- q1d – Once daily
- q24h – Every 24 hours
- q2h – Every 2 hours
- q2wk – Every 2 weeks
- q3h – Every 3 hours
- q4-6h – Every 4 to 6 hours
- q5min – Every 5 minutes
- q6h – Every 6 hours
- q72h – Every 72 hours
- q8h – Every 8 hours
- qAM – Every morning
- QD – Quaque die (every day, once daily)
See all 77 prescription abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.