q12h

Medical abbreviation · Prescription

q12h
Stands forEvery 12 hours
CategoriesMedical

q12h stands for Every 12 hours, a prescription abbreviation.

Twice-daily dosing at strict 12-hour intervals, usually 0900 and 2100 or 0600 and 1800. It is used for drugs where consistent spacing matters, such as enoxaparin treatment doses, vancomycin and many extended-release oral products.

Example: Enoxaparin 1 mg/kg subcut q12h for DVT treatment.

Usage notes

Also written Q12H or q 12 hr. In outpatient practice BID and q12h are often used interchangeably, but in hospitals they can map to different scheduled times in the electronic medication record. Extended-release opioids such as OxyContin are labeled for q12h dosing.

More prescription abbreviations

  • NTE – Not to exceed
  • OD – Omni die (once daily)
  • OJ – Orange juice
  • PC – Post cibum (after meals)
  • PRN – Pro re nata (as needed)
  • q.s. – Quantum sufficit (a sufficient quantity)
  • 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

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.