What does Q8H mean on a prescription?
Q8H means every eight hours around the clock — three doses in 24 hours, evenly spaced, including overnight if needed.
- Means:
- every 8 hours
- From:
- quaque 8 hora
- Type:
- How often
- Also written:
- q8h, q8°, Q8H, q 8 h
What it means in practice
Q8H is the strict-interval version of TID. For antibiotics in particular the even spacing matters, because it keeps the drug concentration above the level needed to suppress bacteria between doses.
Example on a prescription
Amoxicillin 500 mg PO Q8H x 7 days
Take one 500 mg amoxicillin capsule by mouth every eight hours for seven days — for example 7am, 3pm and 11pm.
Commonly confused with
- TIDTID is three times a day within waking hours. Q8H fixes the gap at eight hours.
- Q6HQ6H is every six hours, four doses a day.
Worth knowing
For antibiotics, taking Q8H doses bunched into the day leaves a long overnight gap and can let bacterial levels recover. If the spacing is difficult, ask about a medicine with simpler dosing rather than compressing the schedule.
Frequently asked questions
Is Q8H the same as three times a day?
Both are three doses, but Q8H means strictly every eight hours. TID allows the three doses to fit your waking day.
What times are Q8H?
Any three times eight hours apart, such as 7am, 3pm and 11pm. Pick a set you can keep to consistently.
Related abbreviations
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This page explains prescription notation for general information. It is not medical advice and does not replace your prescriber or pharmacist. If a label is unclear or differs from what you were told, check with your pharmacy before taking the medicine.