What does QHS mean on a prescription?
QHS means every night at bedtime. A medicine prescribed QHS is taken once daily, in the evening, shortly before you go to sleep.
- Means:
- every night at bedtime
- From:
- quaque hora somni
- Type:
- When
- Also written:
- qhs, q.h.s., QHS, HS
What it means in practice
QHS comes from quaque hora somni, “each hour of sleep”. HS on its own means the same thing. Bedtime dosing is used when a medicine causes drowsiness, when it works best overnight such as some statins, or when it would otherwise interfere with your day.
Example on a prescription
Atorvastatin 20 mg PO QHS
Take one 20 mg atorvastatin tablet by mouth each night at bedtime.
Commonly confused with
- QDQD is once a day at any consistent time. QHS specifies bedtime.
- QPMQPM is every evening, which is not necessarily immediately before sleep.
Frequently asked questions
What does QHS mean on a prescription?
Take it every night at bedtime — one dose a day, in the evening before sleep.
Is QHS the same as HS?
In practice yes, both mean at bedtime. QHS adds 'every', so it reads as every night at bedtime.
What does PO QHS PRN mean?
By mouth at bedtime, as needed — take it at night only if you need it, such as a sleep aid.
Related abbreviations
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This page explains prescription notation for general information. It is not medical advice and does not replace your prescriber or pharmacist. If a label is unclear or differs from what you were told, check with your pharmacy before taking the medicine.