Deciphering Dosage Timing With 4-Times-a-Day or Every 6 Hours (2024)

QID and Q6H are both medical abbreviations used on prescription medications. QID medications should be taken four times a day, while Q6H should be taken every six hours. While this may seem redundant, it's not. There's a key difference.

With QID medications, you need to space out your doses, but not by a specific number of hours. You can take your last dose before going to bed instead of waking up at night to take it.

Medications labeled Q6H need to be taken following a specific schedule. You may need to wake up at night to take a dosage to make sure you're spacing each dose six hours apart.

This article explains the medical abbreviations QID and Q6H and covers other common medical terms used to describe how and when to take your medicine.

Deciphering Dosage Timing With 4-Times-a-Day or Every 6 Hours (1)

Medical Abbreviation QID

The medical abbreviation QID means four times a day. It may be written as QID, qid, or q.i.d. It is Latin for quater in die, which translates to "four times per day."

You only need to take QID medication when you're awake. Your prescription may come with the note "QID while awake" or something similar to clarify that this is the case.

The following times of day are optimal for taking QID medication, and the time between doses doesn't have to be exact:

In the morning
Around noon
In the evening
At night before bed

Difference Between Drug Dose and Dosage

Medical Abbreviation Q6H

Whether written as Q6H, q6h, or q.6.h., this medical abbreviation stands for the Latin phrase quaque 6 hora, or "every six hours." Q6H medications are categorized as around-the-clock (ATC) medications. ATC medications need to be taken at set intervals so the drug levels in your blood stay consistent and high enough.

ATC medications include drugs for heart disease and high blood pressure as well as blood thinners (drugs that keep your blood from clotting). Severe pain is also often managed with ATC dosing. Pain tends to come back quickly once the dose wears off. Taking the right dose at set intervals may help keep your pain from spiking.

If you're prescription says Q6H, you can take your doses at the following times or at any other time of day as long as you keep a six-hour regimen:

First dose at 6:00 a.m.
Second dose at 12:00 p.m.
Third dose at 6:00 p.m.
Fourth dose at 12:00 a.m.

Taking Around-the-Clock Medications

Common Medical Abbreviations on Prescriptions

You may see these abbreviations on your prescription, and your pharmacy should give you written instructions explaining them.

Abbrev.	Latin	Meaning	Other Info
PO	per os	Orally (by mouth)
BID	bis in die	Twice a day
TID	ter in die	Three times a day
QID	quater in die	Four times a day
Q4H	quaque 4 hora	Every four hours
Q6H	quaque 6 hora	Every six hours
Q8H	quaque 8 hora	Every eight hours
Q12H	quaque 12 hora
PRN	pro re nata	As needed	Usually for mild or intermittent symptoms
AC or QAC	ante cibum or quaque ante cibum	Before a meal	May be followed with a set amount of time before eating, such as one hour
PC	post cibum	After a meal
IM	—	Intramuscular (into the muscle)	For injections only
SubQ, SQ, or SC	—	Subcutaneous (under the skin)	For injections only
IV	—	Intravenous (in a vein)	Given via an IV line or port
GTT	gutta	Drops	For eye drops, ear drops, etc.
OD	oculus dexter	Right eye	For drops or ointments
OS	oculus sinister	Left eye	For drops or ointments
OU	oculus uterque	Both eyes	For drops or ointments

Some abbreviations, like QD (once a day), QOD (every other day), and others, can be easily confused with one another and are no longer used. These terms must be written out because they can contribute to medication errors.

Preventing Medication Errors

Medication errors can and do happen. They often cause side effects, which may require an emergency room visit or hospitalization. Some errors lead to death, including those involving opioid medications. It's estimated that half of these errors are preventable.

Help prevent medication errors by being your own advocate:

Make sure the prescription you get is the prescription your provider intended: Check the instructions on the medication you pick up to make sure that they match the instructions from your healthcare.
Request plain language: You can always ask your provider to write out your prescription instructions in terms you can clearly follow.
Ask for a prescription to be digitally sent to your pharmacy: This may reduce the likelihood of handwriting being misinterpreted.

7 Questions to Ask Before Taking a Prescription

Summary

Healthcare providers often use shorthand terms when prescribing a drug. They may use abbreviations on prescriptions, such as QID and Q6H. These and other forms of medical shorthand are well known in the healthcare setting. But using them is by no means a required practice.

Be sure your provider or pharmacist clearly explains how and when to take your medicine. Ask them to clarify what you do not understand or would like to know about this drug. This can help prevent medication errors.

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