Vanco trough, slightly high vs low.

[Sparda29]

Advertisement - Members don't see this ad

Recently we've been doing a trial of pharmacists dosing Vanco and recommending doses to docs. I've seen that most of my dosing recommendations come back with slightly high troughs vs low when the doc doesn't accept my recommendation. (20-22 when I recommend, 7-9 when docs dose)

I'm guessing its because I don't take unexpected rises in SCr into consideration when recommending doses.

Isn't slightly higher better than low for patients with stuff like pneumonia, bacteremia, sepsis, etc.

 

[PharmDstudent]

Recently we've been doing a trial of pharmacists dosing Vanco and recommending doses to docs. I've seen that most of my dosing recommendations come back with slightly high troughs vs low when the doc doesn't accept my recommendation. (20-22 when I recommend, 7-9 when docs dose)

I'm guessing its because I don't take unexpected rises in SCr into consideration when recommending doses.

Isn't slightly higher better than low for patients with stuff like pneumonia, bacteremia, sepsis, etc.

Your department needs a kinetics calculator that you can use to get the initial dose, and then you would round slightly down if your dosing is a bit of an overshoot. I almost always have to round down LTAC doses.

 

[deleted205891]

Considering the way some hospitals draw troughs, it may not be a true trough anyway. For example, ours draws troughs around 6-7am (if it's a morning trough) when the next vanc administration time is 10am. If this is the case at your hospital, going slightly above range is fine.

 

[joetrisman]

5-15

 

[Sparda29]

Your department needs a kinetics calculator that you can use to get the initial dose, and then you would round slightly down if your dosing is a bit of an overshoot. I almost always have to round down LTAC doses.

We have one. The docs here are afraid to do anything more than 1gram q12h. I remember one time I suggested something like 1.5 grams q8h and the doc looked like she was going to **** herself.

 

[WVUPharm2007]

Jesus H Christ.

First off, the goal is either 10-15 or 15-20 depending on the site (higher for stuff like osteo.) Consult the actual guidelines. Get them here. Anything under 10 is a failure in therapy.


Second off, all that nephrotoxicity nonsense is just a remnant of the old "Mississippi Mud" days when Vanc was manufactured poorly. The patients will be fine.

And I've been working retail for 2 and a half years. 🙄

 

[Digsbe]

My last rotation did a lot of pharmacist vanc dosing and monitoring. Their goal was 15-20 trough levels. The pharmacist I rounded with said if their kidneys are fine being a little high is fine, typically the dose wasn't adjusted if a trough of 22 or so came back. They seemed to focus more on keeping it between 15-20 and not wanting it too low due to antibiotic creep, wanting to stay above the MIC, and seeing improvements in WBC count. She also told me the nephrotox stuff was way overplayed and having a slightly high trough in patients with healthy kidneys isn't going to be a serious concern. She did tell me being slightly high is better in most cases than low for serious things and if you have a patient with an infection in an area that is harder for the drug to get too or wouldn't get as much exposure. I remember on my rotation a trough was drawn roughly 6 hours after a q12 dose was given so it came back higher than it should. Other times it was seen where nurses administered a dose too frequently like once every 7-8 hours instead of q12.

At the institution the pharmacist is pretty much independent in it. They order the lab tests, do the monitoring, order new doses, make changes to doses and all that good stuff. They had a protocol set up where once the patient was put on the protocol they could do whatever they wanted without much interference.

 

[Music Man]

Your pharmacy needs to grow some balls and mandate Vanc dosing, but only after all of your Pharmacists have read the guidelines and understand kinetics better than your docs.

Lower troughs only contribute to higher resistance rates, longer LOS, more treatment failures, etc. Some of your MD's are probably ordering peaks, too, which does nothing except increase healthcare costs and inconvenience patients with unnecessary and painful needlesticks.

 

[Sparda29]

Your pharmacy needs to grow some balls and mandate Vanc dosing, but only after all of your Pharmacists have read the guidelines and understand kinetics better than your docs.

Hopefully that's what this vancomycin tracking project will lead to. It's not gonna fly with the old pharmacists here though. I'm the only full timer in their 20s other than the clinical pharmacist, 2-3 in their late 30s early 40s, and the rest in their 50s-60s.

 

[confettiflyer]

Second off, all that nephrotoxicity nonsense is just a remnant of the old "Mississippi Mud" days when Vanc was manufactured poorly. The patients will be fine.

Bingo. Most of the nephrotox cases were back when the stuff was 70% pure or so. Monotherapy w/ vanco isn't really associated w/ AKI, throw in some other agents and you might have something to worry about, but good luck teasing out whether it was a consequence of dz progression or what.

20-22? who cares, keep steady...unless they were obese and it was the first trough drawn prior to the 4th dose, you might be looking at some compartment shifts in a few days.

 

[mustang sally]

This is a great thread. Had a patient on a q24 hour interval come back at a 24 the other day and was not sure how to react to that since it was just a little bit high.

 

[OmiPharmD]

This is a great thread. Had a patient on a q24 hour interval come back at a 24 the other day and was not sure how to react to that since it was just a little bit high.

In this case we would check to see if the trough out of goal range is due to a decline in renal function (trend in SrCr and urine output).

If renal function is stable then decrease the dose by 250 mg and continue same frequency.

If the UO has gone to poo then we're probably switching to intermittent dosing.

 

[confettiflyer]

This is a great thread. Had a patient on a q24 hour interval come back at a 24 the other day and was not sure how to react to that since it was just a little bit high.

assuming RF is stable then i'd bump the dose down the min. increment and draw another trough later. you can be a hero and calculate pt specific PK...or make your student do it

 

[kvl1027]

We were filling IV home infusion for a patient on vanco, Trough came back at 21. Who cares! Anyway, the lab listed it as a critical value, the nurse called the doc, doc decreases the interval to q18h, next trough was 6.....

If the a safe goal of therapy in someone with a severe infection can be 15-20, then it would also be safe in someone with a less severe infections (although a bit overkill). Better to be slightly high, in my opinion, than low.

A sub par regimen will kill the patient faster than slightly high vanco troughs. Plus the nurse probably drew the trough while the drug was infusing anyway..so...

 

[PharmDstudent]

We were filling IV home infusion for a patient on vanco, Trough came back at 21. Who cares! Anyway, the lab listed it as a critical value, the nurse called the doc, doc decreases the interval to q18h, next trough was 6.....

If the a safe goal of therapy in someone with a severe infection can be 15-20, then it would also be safe in someone with a less severe infections (although a bit overkill). Better to be slightly high, in my opinion, than low.

A sub par regimen will kill the patient faster than slightly high vanco troughs. Plus the nurse probably drew the trough while the drug was infusing anyway..so...

This is really the heart of the problem - how other health professionals react to trough values.

 

[confettiflyer]

This is really the heart of the problem - how other health professionals react to trough values.

It takes hard work to tamp this down

Plus the nurse probably drew the trough while the drug was infusing anyway..so...

Haha...I've seen these, you do a double take when the trough is 41, haha.

 

[Sparda29]

I always get this from the docs. "But the patient is a little old lady." Then I have go to and say "but but my calculator says that the dose should be X". Then I get the "nah let's just start slow and work our way up."

 

[Carboxide]

Vanco dosing is not that hard. You just have to look at the SCr trends and also make sure for older people you are using an adjusted SCr. Just because your 85 year old lady has a SCr of 0.4 does not mean you should use that in the eq.

If the level is off, you can always look to see when the dose was hung vs when the trough was taken.

At my hospital we do not ask the MDs to change the dose. Pharmacy adjusts it themselves based on trough. It has linear PK so it's pretty easy...if trough is 25 at 1gm Q12 with goal of 15 to 20, then drop to 750 q 12 and you will get a 25% decrease in trough as well.

 

[TheThorn]

I always get this from the docs. "But the patient is a little old lady." Then I have go to and say "but but my calculator says that the dose should be X". Then I get the "nah let's just start slow and work our way up."

Yes, but in fairness, they're the ones who will have to deal with the adverse effects of vanc toxicity, not you, and it's ultimately their license on the line.

 

[WVUPharm2007]

Yes, but in fairness, they're the ones who will have to deal with the adverse effects of vanc toxicity, not you, and it's ultimately their license on the line.

Fearing vanc toxicity is like fearing alien abduction. It doesn't really happen. When it "does" its because the patient was taking something like gent that actually is nephrotoxic. Just jot down "Vanc, pharmacy to dose per P&T protocol" (assuming there is one...I would hope there is one) and its now the hospital's problem. Someone competent will take over and they will be properly dosed. The bigger fear here is resistance, not 1 in a million nephrotoxicity.

And for the record, just about anything is better than being under 10. 22? Please...just keep it as is. Unless you want to make a minor change and have the IV techs do a custom bag. 1.5g q12 becomes 1.4g q12. It'd be a giant waste of everyone's time...but if that's what makes you feel safe...whatever.

 

[Music Man]

Calculators? Only rookies use those. I just want to laugh when I see Pharmacists change Vanc from 1g q12hr to 1250mg q12hr when the ss trough came back at 8.7 and they have meningitis. It's amazing how many of you guys here--and at my hospital--have not so much as read the guidelines and lack anything beyond a minimal understanding of this drug. Usually I am only concerned when the patient just came from CT and had Isovue on board. When their SCr triples overnight, I don't want anyone blaming me so I dose conservatively initially. After AM labs come back normal, anything goes.

Oh yeah, Vanc nephrotoxicity does happen. Just remember, though, unlike so many nephrotoxic drugs, it's reversible. Everyone here should know that, even if you haven't read the guidelines.

 

[confettiflyer]

1.5g q12 becomes 1.4g q12. It'd be a giant waste of everyone's time...but if that's what makes you feel safe...whatever.

who on god's green earth would ever do that? 1.4gm is ******ed. our policy even states to go to the next 250mg increment.

 

[confettiflyer]

Just because your 85 year old lady has a SCr of 0.4 does not mean you should use that in the eq.
.

There's a decent amount of lit supporting using the SCr as is without rounding to 1 in old people. Stopped doing that a long time ago...but obviously clinical decision making still applies, so I'll fudge around with it based on the pt.

There was another meta-analysis that suggested not even using weight at all...which I thought was weird, but sortof makes sense with all this jiggering of the orig. CG equation to adjust for populations.

Work in progress, best is obtaining and calculating pt specific PK but that's not always feasible given renal function fluctuations and time required to get a dose.

Or you can just give everyone linezolid, hah.

 

[Sparda29]

What calculator do you mean for vancomycin? I've never done anything like that - just look at their history (if had vanco before) and renal fxn... Start them at the empiric for their age (I work in peds) and if concerned about a low/high trough draw one sooner rather than later.

Clinical Pharmacist at my hospital developed a pretty sweet CrCL calculator + vancomycin PK calculator on Excel. Literally all you have to enter is: Age, Male or Female, SCr, height and weight, vancomycin dose, interval, and infusion time.

 

[Carboxide]

There's a decent amount of lit supporting using the SCr as is without rounding to 1 in old people. Stopped doing that a long time ago...but obviously clinical decision making still applies, so I'll fudge around with it based on the pt.

There was another meta-analysis that suggested not even using weight at all...which I thought was weird, but sortof makes sense with all this jiggering of the orig. CG equation to adjust for populations.

Work in progress, best is obtaining and calculating pt specific PK but that's not always feasible given renal function fluctuations and time required to get a dose.

Or you can just give everyone linezolid, hah.

Linezolid is not a good choice for MRSA bacteremia. I'd do dapto before linezolid any day. Plus we shouldn't be using dapto/linezolid/ceftaroline/tigecycline if we don't have to...prevent spread of resistance, etc etc.

In older people I typically use rounding up of SCr. That is protocol at my hospital. But I might take an earlier trough, especially if it's q24h dosing, just to see how it looks. If it's very low I might adjust sooner than after the 4th dose.

22 is better than 8 as a trough...but neither are OK. If your trough is 22 on 1.5 q12h, you can easily knock the dose down to 1250 q12h and be in a safer range. If your trough is high, you can easily adjust for it in most patients. You guys are acting like when you draw a trough of 22, you have to pick between keeping that dose or going down to a trough of 5...you can easily pick a new dose that lands in target range.

 

[confettiflyer]

Linezolid is not a good choice for MRSA bacteremia. I'd do dapto before linezolid any day. Plus we shouldn't be using dapto/linezolid/ceftaroline/tigecycline if we don't have to...prevent spread of resistance, etc etc.

I was being half-facetious. I do see an argument for linezolid in septic young people with lungs full of fluid from some raging PNA without AKI because of the extremely high clearance of vanco despite high/frequent dosing. I'm talking about those pt's who will be dead < 24hrs before you can even assess whether that 2gm load helped.

[/quote]

In older people I typically use rounding up of SCr. That is protocol at my hospital. But I might take an earlier trough, especially if it's q24h dosing, just to see how it looks. If it's very low I might adjust sooner than after the 4th dose.

Check out the Winters & Guhr study on CrCl, we may be doing a disservice to our elderly pt's by underdosing them especially given the overblown risk of nephrotoxicity.

22 is better than 8 as a trough...but neither are OK. If your trough is 22 on 1.5 q12h, you can easily knock the dose down to 1250 q12h and be in a safer range.

I would do a change at 22, to be fair... you'll just look incompetent when you chart "everything is good in the 'hood...continue same" because you're probably not following institutional protocol at this point.

If your trough is high, you can easily adjust for it in most patients. You guys are acting like when you draw a trough of 22, you have to pick between keeping that dose or going down to a trough of 5...you can easily pick a new dose that lands in target range.

People be scared.

 

[PharmDstudent]

Clinical Pharmacist at my hospital developed a pretty sweet CrCL calculator + vancomycin PK calculator on Excel. Literally all you have to enter is: Age, Male or Female, SCr, height and weight, vancomycin dose, interval, and infusion time.

We have the same kind of deal in an Excel program, but the calculator that we use only requires age, M/F, SCr, height, and weight. Once you plug in the numbers and it gives you the dose and frequency, then the pre-built order set will give you the appropriate infusion time. It's the easiest **** ever, but it will tend to overshoot for LTAC patients.

 

[PharmDstudent]

It takes hard work to tamp this down

It's so dumb, you know?

 

[confettiflyer]

It's so dumb, you know?

We've gotten pretty good on the whole "oh, it's on pharmacy protocol, let them handle it" thing. By policy critical values (lol, vanco trough > 10 the way it's put in) have to be reported to the physician. All of our hospitalists are pretty good about not doing anything...the only time they call is if something is weird (trough of 41?) where then i have to ensure i know what's going on (oh i talked to the nurse, lab was drawn as the infusion was running).

Basically, pharmacy has to know what it's doing and physicians have to trust that we're not incompetent. Some hospitals, it's a chicken-egg thing.

 

[Sparda29]

We have the same kind of deal in an Excel program, but the calculator that we use only requires age, M/F, SCr, height, and weight. Once you plug in the numbers and it gives you the dose and frequency, then the pre-built order set will give you the appropriate infusion time. It's the easiest **** ever, but it will tend to overshoot for LTAC patients.

Ahh, I'm guessing it's kinda a reverse of our program where the target trough is built into the equation. I was just thinking of asking the clinical pharmacist to set up the program so all we have to enter is the target trough and it gives us the best dose.

 

[redxiii1313]

So I got a pt case that's gotten me confused. A 48 yof is admitted into the icu, she's a chronic alcoholic and has infiltrates in her lower right lung suggestive of pneumonia. she weight 68 kg and has pretty good kidney fx (scr = 0.4 and crcl was 140 ml/min). I decided to dose the pt 1 g q 8 hrs. Trough before the 4th dose comes back at 25 and scr jumps up to 0.8. 4th dose is held and vancomycin is readjusted to 1 g q 12 hr starting 12 hours after 3rd dose. Today pt's scr is 1.8 and trough came back at 44. I talked with the nurse taking care of the pt and states that the pt is generating urine but it seems like something is obstructing her kidneys and are consulting the urologist. It kind of kills me to think that I may have gone overboard and overdosed the pt but at the same time is this d/t vanco nephrotoxicity or some other factor?

 

[Praziquantel86]

So the other question here, and I'm surprised no one has brought this up, is what is the trough telling us? It's a surrogate for AUC, and it actually doesn't perform all that well as a surrogate (probably underestimates the AUC in ~25% of cases). If you're using a fancy PK calculator to come up with your doses (and estimated PK parameters), why not target the thing you're actually trying to meet? Based on the sneak peaks that have been given of the upcoming vanco guidelines, AUC is going to be re-emphasized as a goal measure (and yes, that means two-level kinetics are going to be making a comeback).

The guidelines that we have now were based on the best-guess of what we should be doing, and the literature that has come out since that time suggests that the mark may have been missed somewhat. It's also worth mentioning that this literature, and really the whole guideline, applies only to S. aureus. An often overlooked fact.

As far as the vanc nephrotoxicity goes, I think it's been pretty clearly shown that there is a dose- and duration-dependent increase in nephrotoxicity with vancomycin. Whether minor creatinine bumps are clinically relevant is a different story, but they certainly can and do occur.

So to answer the original question, I'd aim for a midrange trough and call it a day. That way you don't have to worry about people freaking out about red values in the EMR or the dreaded <10 trough.

 

[Sparda29]

So to answer the original question, I'd aim for a midrange trough and call it a day. That way you don't have to worry about people freaking out about red values in the EMR or the dreaded <10 trough.

That's the thing though. Even in a patient like me, age 26, height 5'9", weight 100kg, SCr 1.0, these docs would probably want to start me on Vancomycin 1gm q12h for pneumonia instead of something more appropriate like 1750 mg q8h.

 

[joetrisman]

So the other question here, and I'm surprised no one has brought this up, is what is the trough telling us? It's a surrogate for AUC, and it actually doesn't perform all that well as a surrogate (probably underestimates the AUC in ~25% of cases). If you're using a fancy PK calculator to come up with your doses (and estimated PK parameters), why not target the thing you're actually trying to meet? Based on the sneak peaks that have been given of the upcoming vanco guidelines, AUC is going to be re-emphasized as a goal measure (and yes, that means two-level kinetics are going to be making a comeback).

The guidelines that we have now were based on the best-guess of what we should be doing, and the literature that has come out since that time suggests that the mark may have been missed somewhat. It's also worth mentioning that this literature, and really the whole guideline, applies only to S. aureus. An often overlooked fact.

As far as the vanc nephrotoxicity goes, I think it's been pretty clearly shown that there is a dose- and duration-dependent increase in nephrotoxicity with vancomycin. Whether minor creatinine bumps are clinically relevant is a different story, but they certainly can and do occur.

So to answer the original question, I'd aim for a midrange trough and call it a day. That way you don't have to worry about people freaking out about red values in the EMR or the dreaded <10 trough.

Me thinks the issue with true mics and testing methods makes this a problem

 

[MackandBlues]

I really like globalrph's vancomycin dosing calculator. You input the patient specific stuff and it will generate a regimen for you and then right below it you can input your regimen and it will calculate the patient's projected peak and trough.

 

[xiphoid2010]

So I got a pt case that's gotten me confused. A 48 yof is admitted into the icu, she's a chronic alcoholic and has infiltrates in her lower right lung suggestive of pneumonia. she weight 68 kg and has pretty good kidney fx (scr = 0.4 and crcl was 140 ml/min). I decided to dose the pt 1 g q 8 hrs. Trough before the 4th dose comes back at 25 and scr jumps up to 0.8. 4th dose is held and vancomycin is readjusted to 1 g q 12 hr starting 12 hours after 3rd dose. Today pt's scr is 1.8 and trough came back at 44. I talked with the nurse taking care of the pt and states that the pt is generating urine but it seems like something is obstructing her kidneys and are consulting the urologist. It kind of kills me to think that I may have gone overboard and overdosed the pt but at the same time is this d/t vanco nephrotoxicity or some other factor?

You can't always be sure. Vanc is often started when the patient is going septic, which in itself leads to renal failure also. And in alcoholics, you got the possible hepatorenal syndrome to consider. Pre/intrinsic/post renal causes, hx of injury, other drugs on board, too many possibilities to consider. Better to leave the diagnosis to physicians instead of second guessing yourself.

As long as you can justify the initial calculations, there are some patients whose kidney is going to crap out for one way or another, vancomycin or not, maybe just because somebody sneezed in their direction.

 

[Praziquantel86]

Me thinks the issue with true mics and testing methods makes this a problem

That's also an issue...but it doesn't make a difference if you target a fixed AUC goal for each patient, assuming that the MIC is no more than 1 - goal AUC/MIC is unachievable with anything higher anyways. Most of the automated systems way over call the true MIC, which is a big problem.

 

[confettiflyer]

I really like globalrph's vancomycin dosing calculator. You input the patient specific stuff and it will generate a regimen for you and then right below it you can input your regimen and it will calculate the patient's projected peak and trough.

it's handy, but unless you understand the steps behind the calculator, you could royally screw things up. clinical judgement still applies on empiric therapy...i do use it for revision kinetics though when i'm too busy to crank it out manually.