i-base

Q12H

Q12H (or q12H) – an abbreviated term for timing medication doses.

q8H means every 8 hours.This is not the same as three times a day (tid or TD).

q12H means every 12 hours. This is not the same as twice-daily (bid or BD).

q24H means every 24 hours. This is not the same as once-daily (qd or QD).