In a prescription such as this:

omeprazole 20 mg BID

I know BID means two times per day.

However, does this mean to take half the dose of 20 mg (10 mg) in the morning plus 10 mg in the evening?

Or does it mean to take the full dose (20 mg) in the morning plus 20 mg in the evening?

  • 2
    It means take 20 mg in the morning and 20 mg in the evening.
    – Carey Gregory
    Jan 24, 2018 at 21:24

1 Answer 1


As you've stated BID = bis in die = twice a day. According to a standard dosage sheet from the University of Florida, BID = every 12 hours.

However, I was reading a forum for nurses [See References] and there seems to be variations on BID (roughly 8-12 hours apart) depending on the hospital.

If possible, contact your nurse/physician for the clearest clarification.


University of Florida Standards: http://professionals.ufhealth.org/files/2011/11/1007-drugs-therapy-bulletin.pdf

Forum: http://allnurses.com/first-year-after/bid-strictly-every-795661.html

  • 3
    It means twice daily, which means every 12 hours. Local hospital policy might allow some leeway, but that's what it means universally.
    – Carey Gregory
    Jan 24, 2018 at 20:51

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