What does "2 qd" actually mean?
Last night I had a prescription that said "2 qd" — it was a phoned-in prescription. I filled it, thinking nothing of it, and low and behold I see it has been edited to some different directions. "WTF?" I say to myself, pulling out the hard copy. Nope, it definitely says "Π qd" (That's as close to a Unicode approximation to the symbol for 2 that I can come up with.)
"Um, so why did you change this?" I ask, handing the QA pharmacist the hard copy and the edited label.
"Because it was wrong," she says.
"No, it wasn't," I say, handing over the script written by her hand. "2 qd means '2 tablets once daily'."
"You don't know that," she says. "What if the doctor means take 1 tablet in the morning and 1 tablet 4 hours later, or 1 tablet twice a day?"
"Well then the doctor should write that."
"Sometimes they don't."
"I see. *pause* I was always taught that 2 qd means '2 tablets once daily' and if the doctor wants twice daily dosing, the script should say 'BID' otherwise the doctor — not the pharmacist — has made a mistake. And that 2 qd absolutely means 2 tablets/capsules/whatever once daily, with no ambiguity."
"Well, I like to put 'Take 2 tablets every day as directed.'"
We argued a bit after that, but the trouble with sticking "as directed" on there is a nifty way of a pharmacist doing a little CYA, which isn't necessarily a bad thing. The script technically doesn't say it, and generally speaking, the patient hasn't been "directed" in how to do anything, so it's actually not correct to do that. What if the script is for meloxicam or nabumetone?
To aid in the discussion, here's a brief Latin recap for those that have forgotten it, or never learned what the abbreviations actually meant in the first place. Unfortunately, they're not much help, either:
- q: quaque: "every"
- qd: quaque die: "every day" which is generally understood to be "once a day" or "once daily"
- qX°: every X hours
- po: per os: "by mouth"
- od/os/ou: oculus dexter ("right eye"); oculus sinister ("left eye"); oculus uterque ("both eyes")
And so on.
For me, I will continue to write "Take 2 tablets once daily" when I see "2 qd". But to others, that means something different, and I think it's important that prescribers know that that it means something different to each pharmacist. I mentioned this phenomenon in my Chantix prescribing tutorial, and it applies here as well. There is indeed ambiguity, where there should ideally be none.
And it so happens that this presents the perfect opportunity to test out my new polling toy. So I've included 2(!) polls for finer-grained results. We'll pretend we're dealing with tablets for the sake of simplicity. If you are not in the medical field, please vote "Other medical personnel". The poll will open a new window for each poll which is annoying, but there doesn't seem to be a way around this. And feel free to elaborate in the comments — I really had no idea until yesterday that this was something not everyone agreed on.
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I am an RN. Most hospitals have outlawed QID and QD abbreviations. We actually have to write out four times daily, or once daily. So I never run into this problem personally,
But when I first saw it written on your post, it did look a little ambiguous.
Comment by greensunflower — August 9, 2007 @ 4:31 am
Definitely something I would call the doc and clarify. It's a perfect example of why such abbreviations are not permitted in most hospitals.
~Raven
Comment by somedaynurse — August 9, 2007 @ 4:12 pm
Agree with you, my friend: two tablets once a day.
Suggest to you, my friend: it is time for prescribers to scrap Latin abbreviations and apothecary units, and write their directions in the WORDS of the prevailing language of the country, and dose in metric units only.
Comment by The Ole' Apothecary — August 9, 2007 @ 6:25 pm
Why would a doctor prescribe two tablets taken at the same time? Why not prescribe a higher dose?
Comment by Crystal — August 10, 2007 @ 2:32 pm
You are confusing "dose" with "strength" and there are many reasons for it.
First off, "dose" is the amount of drug taken at whatever time interval, and has nothing to do with the strength of the tablet or capsule.
Secondly, the amount a person takes can vary from day to day, especially in the case of something like warfarin.
Thirdly, sometimes the highest strength of something isn't enough, so a person might need to take 1 or 2 of a lower-strength version to get the amount that they need. Or sometimes 2 of the highest strength of the drug, too.
There are many, many reasons; these are just a few.
Comment by RJS — August 10, 2007 @ 5:06 pm
2 qd has always meant 2 tablets once daily. Take Biaxin/ Biaxin XL….. biaxin directions 1 tablet 2 times daily
( 1 BID) Biaxin XL direction 2 tablets once daily ( 2 qd). Explicit enough for your partner pharmacist as to why 2 qd means what it does????
Comment by rxkerber — August 10, 2007 @ 9:07 pm
Latin abbreviations should be straightforward enough, but we use different abbreviations in the UK. Every day is od (omni die), and qds means four times a day (quater die summendum).
Comment by ukcommunitypharmacist — August 13, 2007 @ 5:21 pm