Medical Definition of q.h. (on prescription)
q.h. (on prescription): Abbreviation for "every
hour." On a prescription
or doctor's hospital orders, q.h. means every hour. Also written qh
(without the periods).
From the Latin quaque meaning once + h for hour. However it
is written, it is one of a number of hallowed abbreviations of Latin
terms that have been traditionally used in prescriptions to specify
the frequency with which medicines should be taken.
Other examples include:
- q.d. (qd or QD) is once a day; q.d. stands for "quaque die"
(which means, in Latin, once a day).
- b.i.d. (bid or BID) is twice a day; b.i.d. stands for "bis in
die" (which means twice a day).
- t.i.d. (or tid or TID) is three times a day ; t.i.d. stands for
"ter in die" (in Latin, 3 times a day).
- q.i.d. (or qid or QID) is four times a day; q.i.d. stands for
"quater in die" (in Latin, 4 times a day).
- q_h: If a medicine is to be taken every so-many hours, it is
written "q_h"; the "q" standing for "quaque" and the "h" indicating
the number of hours. So, for example, "2 caps q4h" means "Take 2
capsules every 4 hours."
Source: MedTerms™ Medical Dictionary
Last Editorial Review: 5/13/2016
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