Twice daily usually means morning and evening, about 10 to 12 hours apart, while labels saying every 12 hours mean it strictly, antibiotics being the classic strict case, since the drug must stay above the level that suppresses bacteria.
An hour or two of drift on a morning-evening drug is fine; doubling up after a forgotten dose is not, so skip and resume instead. Anchor doses to meals or tooth-brushing, set alarms for strict-interval drugs, and ask the pharmacist which category yours is in.
What to do
Common questions
How many hours apart is twice a day?
Twice a day means two doses in the waking day, and how strict the gap is depends on the drug. For most twice-daily medicines, morning and evening is the honest answer: roughly 10 to 12 hours apart, anchored to breakfast and dinner, which is livable and keeps levels reasonably steady. For drugs where blood levels matter more, antibiotics being the classic case, the label's intent is closer to every 12 hours, because the drug works by staying above a level where it suppresses the bacteria, and long gaps let them recover. Which case is yours: every 12 hours on the label means it strictly, while twice daily usually means morning and evening, and the pharmacist can say in ten seconds. An hour or two of drift on a morning-evening drug is fine; doubling up after a forgotten dose is not, so skip and resume. Anchor doses to meals or tooth-brushing, use alarms for strict-interval drugs, and ask the pharmacist about your specific drug's strictness.