Dosing Amoxicillin is not Rocket Science

All retail pharmacists see this on a daily basis.
A 1 year old get an Rx for some Amoxicillin 250/5. Standard issue. However the sig is “3.4mL tid x10d”.
Now what mother with half a fucking brain is going to know how to measure out 3.4mL? Its Amoxicillin for gods sake, not digoxin or something with a super narrow therapeutic index. 99% of the time these are from a NP or PA.
Let me spell it out for you. Round up or down in 1/2 teaspoon measurements. Why? Its because its what our dosing spoons/droppers have HUGE markings for, and there is a less chance of some dumbass mother giving her crotchfruit 4 teaspoonfuls instead of 4mL.
I know exactly how they get these weird doses. Rather than KNOW the drug or use common sense, they have a little book that says that the ‘dosing for amoxicillin is 22mg/kg/day (or some bullshit like that)’. With calculator in hand (and huge erection in pants) they determine that the proper dose is 3.4534mL of the 250mg/5 solution. They write this magical number down, and send their patients away with a medical hard-on the size of Florida.
I take one look at this, and round up to 1 teaspoonful. Seriously, its Amoxicillin. Its like the douches who write an actual sig for pedialyte. As if you are going to force the baby to drink pedialyte or shove a tube up its ass and dump it in that way.
You think that when we reconstitute the Amoxicillin I count the number of drops in the graduated cylinder? Hell no, I just eyeball it, dump it in, shake, and send it to the mother who’s child is either screaming his/her head off or running around tearing shit off of my shelves (Amoxicillin reconstituted with choral hydrate would be interesting). So your magical 5 digit significant figure dose just got horked out the window by a $4 graduated cylinder.
Reminds me of the time I had my intern calculate a Flagyl compound. She was so proud when she told me that she needed to crush 5.4 tablets of the 500mg Flagyl and mix it with x amount of OraPlus/Choclate Syrup (Flagyl has an ass after-taste. Gotta mask it with Hershey Syrup). I look her square in the eyes, and say “I’ll let you make it if you tell me how the fuck you are going to get 0.4 of a tablet”. InternEgo, meet AngryFist. “Round up to the nearest tablet, and recalculate how much solution to add based upon that “. And who says that I don’t teach anyone anything.
Much like during your crusades in retail, you need to choose your battles. You are exact on the things that count, and you roll your eyes and swear at the NP/PA/CNM/Janitor when they write a stupid sig for a drug that it really doesn’t matter with.

Comments #

Comment by IowaPharmGirl on 2007-11-25 18:27:07 -0800 #

Amen…if an earlier post hadn’t mentioned you being engaged I would propose to you. This happens to us every January when the new residents think they can prescribe whatever they want. I actually received an Rx for amoxicillin, 3.647 ml BID x 10 days. Yikes.

Comment by Brandon on 2007-11-25 18:55:56 -0800 #

Here’s what I wanna know, what was the outcome? Did you call or just change the script to 4ml?
I woulda changed it and never thought about it again.

Comment by StringTheorist on 2007-11-25 19:13:55 -0800 #

*claps* now THIS is what we need to learn in college

Comment by Lisa on 2007-11-25 19:57:00 -0800 #

Here is my question, though it’s unrelated to today’s post, and it’s not my pharmacist’s fault in the slightest. Why does Imitrex come in those big, folding card packages? I can’t easily carry those packages in my purse. They are also a pain in the ass to open. I use a tweezers to get the first layer open (try doing that with a migraine). When I pop it through the next layer, it often breaks and a piece ends up in my carpet.
Anyway, I enjoy your blog, and now I understand why it takes time to fill a prescription.

Comment by Brent Michael Krupp on 2007-11-25 19:57:54 -0800 #

Too bad you don’t call up the prescriber and yell at them. The only reason MDs don’t write stupid prescriptions like that is that during their residencies they’d have gotten yelled at by the nurses for being so dumb. You need to fill in for the absent yelling nurses. =P

Comment by Alex on 2007-11-25 20:04:11 -0800 #

I see this type of dosing at least once a week with suspensions and orapred. Sigs like 1 & 1/8 teaspoon TID on amoxicillin and something like 3.13 ml QD on orapred doesn’t even surprise me any more. In both cases, I’ll just have my tech do 1 tsp TID and 3 ml QD. In my view, when customers (or “patients” to pharmaceutical care generations) measure 1 teaspoon, it is more like a range than an exact amount. I’ll be really impressed if they are measuring out anywhere from 4.5 – 5.5 ml when it says 1 teaspoonful. People tend to overmeasure by at least 1 ml in my experience and complain few days later that pharmacy intentionally shorted them on antibiotic and try to kill them.
I think it’s now almost a common practice for pharmacists to add 6 – 10 ml more when reconstituting suspenions to prevent those type of complaints. It’s sad reality but it keeps everyone happy.

Comment by Haley on 2007-11-25 21:00:22 -0800 #

My cousin got a Nurse Practioner degree online, and my grandmother won’t shut up about how great it is that she can write Rx’s, and how smart she must be and how she had to write a bunch of papers.
Personally, the girl never seemed that bright to me, and after working in a pharmacy and seeing some of the scripts we get, I have to wonder..
Great site, I work at CVS and can relate to many of your entries.

Comment by Scott on 2007-11-26 01:09:54 -0800 #

“Crotchfruit?” I have never heard them called that before. I completely understand some doctors get boners when they can practice medicine to the 5th digit!

Comment by Cathy Lane RPh on 2007-11-26 07:17:05 -0800 #

My eyes are rolling on this…do what’s practical, but let’s try to get it right as possible. Several issues are being discussed, including pediatric dosing, practicality and the metric system, plus the issue of the average grade level of reading comprehension in the USA. Basically, we learned reading skills were at elementary school levels in the 80’s–I don’t know if that is still the case, but I also knew that in the elementary schools in the 50’s through 90’s rounding up or down was also discussed. It doesn’t take but 1.5 seconds more to describe the amount of medicine is the proper dose with the help of a black permanent marker–and I know every shop has at least one for inking out patient names on old script bottles (HIPAA) It doesn’t give me a whole lot of satisfaction to know that ‘my’ grassroots move toward use of mLs and metric system is subverted by fellow pharmacists! Personally, I think that if the simplicity and reliability of a system based on the numbers 1 – 10 were the only system taught in schools, it would revolutionize US grade school math education and maybe, just maybe, the level of practical use of math skills might be higher. (I haven’t studied this, so it is only my opinion of course!) I know that immigrants from most other countries understand the metric system. (I definitely don’t know about immigrants from countries that use the English system.) Lots of education/work is still necessary to this regard. Measuring devices out there have two scales–and, on the metric scale, 3.4 mL could more easily round to 3 mL, as 0.4 is closer to the whole number 3 than 4. Of course, pediatric dosing is a major issue in this discussion. Frequently (an understatement!) drugs are not available with pediatric information, dosing information, etc., but the pink stuff, amoxicillin is one of those that is pretty well-understood for use in kids. Yea, when I started the dose was significantly less than what I used to see ER docs write for even ten years ago due to emergence of resistance, but those little ‘water bags’ (babies) are a heck of lot smaller than older patients, and it’s a ‘duty’ to get the dose right. (There’s always opportunity for a good old phone conversation with the prescriber.) Okay, okay, there’s some leeway on dosing amoxicillin, but hey, we’re only talking about intricacies of metrics with a drug like that! (NOT anything else like anti-epileptic drugs, sedatives, some other antibiotics…) I imagine that the main point to bring up is that there is not a class in pharmacy school called ‘introduction to community education’ or ‘trying to get the point across to a distracted person while a baby is screaming in the background’.

Comment by usmcgf22 on 2007-11-26 12:26:48 -0800 #

Someone at school (StLCoP) just recommended your site to me and I’ve gotta say… funny shit! LMAO… especially at the hate mail! And the intern example here is funny as hell as well!

Comment by Stlcop S on 2007-11-26 16:14:57 -0800 #

This has nothing to do with your post, but had to tell you this story. I just started reading your site, and you are a huge hit at St. Louis College of Pharmacy. Back to the story: A 22 year old girl comes into my pharmacy wanting her BCP filled. She told me she doesn’t want the GENETIC because it MAKES her pregnant. I almost bust out laughing when she spews this line. Of course, I hear my fellow intern and pharmaacist run back and begin laughing. I almost* said to her: “Really, cause I thought it was the sex that made you pregnant.” Just seemed like the kinda story that you would enjoy. Thanks for making my job a little more enjoyable.

Comment by pweb on 2007-11-26 17:35:26 -0800 #

Too true, TAP, too true. Where I used to work there was a local pediatrician who… and I only wish I were making this up… would actually write directions stating to “give slightly more than 2/3 teaspoons” bid, tid, etc. He was a cocky prick too, but you really had to control yourself not call him and just yell “Put away your abacus and slide rule and just fucking write for 1 teaspoon douchebag!!”

Comment by Lynn (RainDrop) on 2007-11-26 21:20:24 -0800 #

What would you say if the mother was paying attention and asked you about the dosing? Reminds me of phenobarb scripts. The pt’s R x says 100mg but we’re giving 97.2mg. Pt is complaining “WHYYYYYYYYYYYYYY”
And we keep shorting them when we give 28.35gm of Hydrocortisone 2.5% but the label reads “30gm”
Love your blogs. Keep up the great work.

Comment by Jmerph on 2007-11-26 21:27:37 -0800 #

I actually got one today that said “Tussionex 480 ml #1, 1 tea po q 12 h” — Obviously I was getting NO WHERE near that one. I called the PA – who sounded like a complete idiot. After telling her it was absurd and irresponsible to write for 480 ml of Tussionex, she said “ok, can you give her half that?” So I said no. I told her that no responsible prescriber would give more than about 120 ml. She actually said to me “well, I looked it up in my PDR, I thought I wrote it right.” I’m thinking – are you shitting me? So I said to her “umm, yea, the DOSE is not the problem here, it is the QUANTITY. Why on earth do you need to give the lady 48 days worth of Tussionex?” She actually said to me “well, I only wanted her to get about 2 weeks worth.” (again, are you SHITTIG ME?) So apparently, this PA could make it all the way thru grad school, but can’t multiply 14 by 10. The really sad thing is that she still was clueless when we hung up, but she finally agreed to let me change the rx to 120 ml. OMG, people trust their lives to these idiots!!

Comment by Biggest Fan on 2007-11-27 02:59:00 -0800 #

As a physician – I have to admit that amoxicillin is what I mess up on most. No, I don’t write 4.13256 ml po TID, but I do get to talking with parents and FORGET to divide the dose, so the script will say to give them the 24 hour dose TID (oops)- so the pharmacist will have to give me a call later when they show up. One day, (ug) she had to call me several times just on amoxicillin. Kind of got to be a joke – so, now when I am staffing the walk-in clinic, I usually call the pharmacy and jokingly ‘warn’ them that I am on! Hasn’t happened the last few times, thank goodness!
My biggest complaint about amoxil is when I see a kid who didn’t get over the ear infection (or whatever) after the full course and realizing the NP didn’t dose it based on the recommended weight for the diagnosis. Just writes the generic 200/5 1 teaspoon TID for 1 week. 90% of the time, the dose was about a third of what it should have been.
Lastly, and I’ve said this before to you, TAP – and this is for all you guys out there filling my scripts…Thanks for being so frickin smart! Seriously, I think you guys rock and I love my PharmD friends who are incredible resources at my hospital. Thanks for watching my back when I write something stupid on a script. Thanks for taking the time to educate me on easier ways to dose meds – I do appreciate it. As for amoxil…I’m trying to get better!!!!! 🙂

Comment by jmerph on 2007-11-27 08:34:19 -0800 #

To Biggest Fan: You are the coolest physician I have ever heard of! Keep up the good work.

Comment by rph3664 on 2007-11-27 11:24:29 -0800 #

And what about doctors who write these incredibly complicated prescriptions for the children of mentally challenged parents? We’re talking about people who can barely remember to feed themselves three times a day who somehow have children (the children are almost always biracial – flame away) and the doctor does indeed do something like “slightly more than 2/3 teaspoonful…..”
Or even better, the parents who take their kids to the walk-in clinic all the time and then never pick the scripts up? We had such a family at my old job, and when I called the doctor and told him what wasn’t going on, we never got anything from them again.

Comment by BlueTech on 2007-11-28 09:50:40 -0800 #

I compounded 120gm of Triamcinolone cream with 6gm of coal tar solution. Does accuracy matter on that?
…And does 6gm really make a difference? All it did was turn white cream into yellow cream.

Comment by Google Account on 2008-07-17 20:06:09 -0700 #

OMG, so funny. My husband just got back from a CVS minute clinic (instead of wait for 2 hours in Kaiser – we were SURE he had OM) and the girls were arguing over what to prescribe to our 3 year old for an ear infection…exactly like you describe. We were crackin’ up reading your post. Thanks!

Comment by Deb ray on 2011-03-25 14:16:49 -0700 #

I’m a mom who just had to take my 1yo in for an ear infection but our regular doc is on vacation so we had to see his PA. I did not get a warm and fuzzy feeling when she wrote the Rx. I of course google what the right dosage should be and I see this site. Now I’m feeling real confident…. I sure hope it’s right. She’s 17.5 lbs and the script is for amox 125mg/5ml susp 80ml. Give 8 mls 2x a day and it doesn’t say for how many days so I’m assuming till gone. Any help is appreciated.

Comment by Josh on 2011-04-22 23:35:53 -0700 #

Deb, as a practicing PA in pediatrics for over 7 years, I can reassure you regarding the dosage given to your child; it seems adequate. However, I should meantion that amoxicillin dosages vary greatly depending on a patient’s age and the type of infection you’re trying to treat. And even within those guidelines, there is a range of acceptable dosages. It’s not something that can simply be googled and give you a concrete/definite answer. I have to say that all the NP and PA bashing on here seems a little childish, not to mention ignorant. The whole 3.456ml dosing story sounds like someone who’s either a student or a recent grad without much experience. There are idiots in every profession, including pharmacists, as I found out the other day when I wrote 1 gm of amoxicillin b.i.d. to a 115lb. 10 year old. And she refused to fill the prescription because she thought it was \too much.\ I guess she didn’t get the memo about high dose recommendations that came out 10+ years ago. The funny thing is that it’s still not even that high of a dose. There are some doctors who believe 3gm or even 4gms per day is acceptable. I humored her by actually doing the math with her over the phone, but she still didn’t get it. So in the end, I told the pharmacist to give the prescription back to the parent so she can go to another pharmacy if she’s not comfortable with the universally accepted pediatric dosing regimens for amoxicillin. lol.