q8h

Medical abbreviation · Prescription

q8h
Stands forEvery 8 hours
CategoriesMedical

q8h stands for Every 8 hours, a prescription abbreviation.

Interval dosing with three evenly spaced doses per day, often at 0600, 1400 and 2200. It is typical for many IV antibiotics, heparin subcutaneous prophylaxis and some antiepileptic drugs.

Example: Heparin 5,000 units subcut q8h for VTE prophylaxis.

Usage notes

Compared with TID, which clusters three doses during the day, q8h maintains coverage overnight. Some time-dependent antibiotics such as piperacillin-tazobactam are given q8h as extended infusions to keep drug levels above the bacterial MIC for longer.

More prescription abbreviations

  • q3h – Every 3 hours
  • q4-6h – Every 4 to 6 hours
  • q4h – Every 4 hours
  • q5min – Every 5 minutes
  • q6h – Every 6 hours
  • q72h – Every 72 hours
  • qAM – Every morning
  • QD – Quaque die (every day, once daily)
  • qds – Quater die sumendum (to be taken four times a day)
  • qh – Quaque hora (every hour)
  • QHS – Quaque hora somni (every night at bedtime)
  • QID – Quater in die (four times a day)

See all 77 prescription abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.

This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.