QHS

Medical abbreviation · Prescription

QHS stands for Quaque hora somni (every night at bedtime), a prescription abbreviation.

Directs a dose to be taken nightly at bedtime, common for sleep aids, statins, some antidepressants and eye ointments. ISMP lists it as error-prone because "qhs" has been misread as "qhr", meaning every hour.

Example: Atorvastatin 40 mg PO QHS; recheck lipid panel in 6 weeks.

Usage notes

From Latin "quaque hora somni", "every hour of sleep". Also written q.h.s. or qhs. ISMP recommends writing "nightly" or "at bedtime" instead. In hospitals QHS doses are usually scheduled around 2100 or 2200, which may not match a patient's real bedtime, so some units let nurses time them to when the patient actually settles.

Related abbreviations

More prescription abbreviations

• q72h – Every 72 hours
• q8h – Every 8 hours
• qAM – Every morning
• QD – Quaque die (every day, once daily)
• qds – Quater die sumendum (to be taken four times a day)
• qh – Quaque hora (every hour)
• QID – Quater in die (four times a day)
• qn – Quaque nocte (every night)
• QOD – Quaque altera die (every other day)
• qPM – Every evening
• qty – Quantity
• qwk – Every week (once weekly)

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.