Lasix Dosing

[HelpPleaseMD]

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For lasix is it a threshold effect where higher doses will not necessarily lead to increased diuresis or is it also dose dependent? I have heard it both ways.

thanks

 

[PlutoBoy]

It is largely dose dependent but the maximum effective dose assuming a relatively healthy subject is 40 mg IV or 80 mg PO. That's where the famous 40 mg IV comes from.

If you have heart failure you may end up needing higher doses due to the other mechanisms at play (such as decreased kidney perfusion).

If you have CKD you will also need higher dosages. The lower your GFR the higher the dose that your patient will need.

After you have determined what is the maximum effective dose, giving increasingly larger doses will result in lower diuresis compared with increasing dosing frequency.

So your attendings are/were right about pee rounds 🙂

Hope that helps.

@HelpPleaseMD

 

[PlutoBoy]

In other words, if you give 40 mg and nothing happens don't give 40 the next time around.

 

[jdh71]

Age plus BUN

 

[HelpPleaseMD]

had an attending adjust dose of lasix from 40 mg to 60 mg in a person for the purpose of increased diuresis. 40 was working btw. from the above, I am assuming that changing to lasix bid would be more effective.

 

[Raryn]

For lasix is it a threshold effect where higher doses will not necessarily lead to increased diuresis or is it also dose dependent? I have heard it both ways.

thanks

Both. There's a threshold below which it won't do anything, and then going up on the dose (to a point) will make it more effective. Threshold varies from person to person depending on their pre-existing exposures and their GFR. If they're on loop diuretics at home and come in decompensated, your initial dose should be at least double, if not 2.5x their home dose. (yes, it only "trended towards significance" in the DOSE trial, but it won't hurt and it saves you some effort) IV preferred initially to PO because of worry about bowel edema (but remember the 2:1 conversion). If a given dose doesn't work, double it and try again.

Infusions are no better than appropriately monitored intermittent dosing, but require less work on the physicians part (i.e. giving a bolus, then following up with the nurse an hour later and giving a higher one as needed is harder than just ordering a drip). The studies everyone quotes don't show that infusions are *worse* just that they *aren't better*, so using them occasionally in the unit is still OK.

Bumex is almost certainly no better than an equivalent dose of lasix, but when you're at very high doses, converting over makes the cardiologist/nephrologist feel better. Also, you can eventually push the doses higher without as much worry about ototoxicity (but this is a rare concern, really it's all about making the person who wants you to order it feel better).

 

[deleted547339]

Age plus BUN

Beat me to it.

 

[PlutoBoy]

had an attending adjust dose of lasix from 40 mg to 60 mg in a person for the purpose of increased diuresis. 40 was working btw. from the above, I am assuming that changing to lasix bid would be more effective.

I would agree with you.

 

[jdh71]

I don't think a "challenge" of Lasix for renal failure is legit unless it's three digits. Serious too.

I use a drip when I'm also using a pressor. Sometimes it does make sense. (I also use a drip if nursing is pissing me off about giving it how I want it.)

I try to avoid any Lasix dosing in the outpatient setting because I don't want that hassle.

I kind of think most of the literature looking at diuretics misses the nuance of how it can be used and how it does get used effectively.

 

[PlutoBoy]

I don't think a "challenge" of Lasix for renal failure is legit unless it's three digits. Serious too.

I use a drip when I'm also using a pressor. Sometimes it does make sense. (I also use a drip if nursing is pissing me off about giving it how I want it.)

I try to avoid any Lasix dosing in the outpatient setting because I don't want that hassle.

I kind of think most of the literature looking at diuretics misses the nuance of how it can be used and how it ties get used effectively.

I never (?) used drips but I know it may be convenient sometimes. I just never got used to it.

I agree with the renal failure thing. I would also add that if you have renal failure and fluid overload please don't give fluids (looking at you ER docs 😛). Treat the pulmonary edema first and do it with a legit dose.

 

[VA Hopeful Dr]

I don't think a "challenge" of Lasix for renal failure is legit unless it's three digits. Serious too.

I use a drip when I'm also using a pressor. Sometimes it does make sense. (I also use a drip if nursing is pissing me off about giving it how I want it.)

I try to avoid any Lasix dosing in the outpatient setting because I don't want that hassle.

I kind of think most of the literature looking at diuretics misses the nuance of how it can be used and how it does get used effectively.

What, you don't love giving lasix for "swollen ankles after work every day"?

 

[IMreshopeful]

Lasix is helpful in refractory hypertension with some element of renal dysfunction. Giving it for just dependent edema seems silly.

 

[PlutoBoy]

Lasix is helpful in refractory hypertension with some element of renal dysfunction. Giving it for just dependent edema seems silly.

Yeah. Don't use thiazide diuretics for hypertension in the setting of significant CKD (GFR<30). Use a loop diuretic. You get more credit if you use torsemide due to its longer duration of action.

And don't forget about spironolactone for resistant hypertension.

 

[PlutoBoy]

What, you don't love giving lasix for "swollen ankles after work every day"?

I use Bumex 😛

 

[jdh71]

If I'm treating you for hypertension something has gone very very wrong. I use nicardipine, esmolol, or nipride

Though sometimes in order to get them the **** out of my unit I end up having to start some stuff orally. I mostly let the hospitals sort it out.

If you're hypertensive in my clinic, I suggest you speak with your PCP about it. I don't even make the assessment in my note. 😀

 

[Cytarabine]

I don't think a "challenge" of Lasix for renal failure is legit unless it's three digits. Serious too.

I use a drip when I'm also using a pressor. Sometimes it does make sense. (I also use a drip if nursing is pissing me off about giving it how I want it.)

I try to avoid any Lasix dosing in the outpatient setting because I don't want that hassle.

I kind of think most of the literature looking at diuretics misses the nuance of how it can be used and how it does get used effectively.

I think there's a weight based calculation for Lasix challenge somewhere, but on renal it seemed we'd often just go for 200 IV

I never (?) used drips but I know it may be convenient sometimes. I just never got used to it.

I agree with the renal failure thing. I would also add that if you have renal failure and fluid overload please don't give fluids (looking at you ER docs 😛). Treat the pulmonary edema first and do it with a legit dose.

Also good to know the amount of fluids in whatever meds youre hanging. Can add up quick

 

[jdh71]

I think there's a weight based calculation for Lasix challenge somewhere, but on renal it seemed we'd often just go for 200 IV



Also good to know the amount of fluids in whatever meds youre hanging. Can add up quick

I usually give 120. And then try 200 with a thiazide. After that I'll ask for renal to deal with the nonsense.

I'm a barbarian.

 

[Cytarabine]

I usually give 120. And then try 200 with a thiazide. After that I'll ask for renal to deal with the nonsense.

I'm a barbarian.

Tangent, but what do you do if anything for refractory 3rd spacing in the unit in a relatively normotensive patient? I was trying to look into the evidence for colloid/diuretic drip for edema in the icu and came across https://clinicaltrials.gov/ct2/show/NCT02055872 which is still recruiting. What are your thoughts on extremity wrapping? Is there any reason not to so long as the heart and kidneys alright?

 

[Instatewaiter]

My 2 cents:

For the guy who has 10 lbs of fluid, intermittent dosing of IV lasix works just fine IMO. If it is a lot of fluid to pull though, lasix drips are nice. Bolus with 40, 80 or 120 based on the continuous dose and then start the drip.

The problems with intermittent dosing is that they often aren't monitored close enough so while in the trials the diuretic effect is the same, in practice, I feel the lasix drips give you more diuretic effect because people aren't vigilant enough about monitoring the urine output with intermittent dosing.

Torsemide is great for outpatient diuretic and tends to be our go-to in our cardiomyopathy folks. First it has pleiotropic effects beyond it's diuretic effects. Most importantly, it doesn't have the problems with gut edema that lasix does. It can be a way to keep people out of the hospital. Bumex is a reasonable alternative.

For thiazide boosters, don't forget about HCTZ- it is dirt cheap, has less hypokalemia than metolazone and works well. Also, don't forget the thiazide should be 30 minutes or so before the loop for maximal effect.

I like extremity wrapping mainly because it seems like it could be beneficial. Part of the way you get into problems with renal dysfunction with diuresis is by pulling more fluid out of the intravascular space than you can reaccumulate from the edema/extravascular space. It makes sense that increasing the external pressure with wrapping would promote movement of fluid from extravascular to intravascular space- minimizing your renal dysfunction and maximizing what you can diurese.

Above the threshold dose, there is a dose dependent effect as others have said above.

Strongly recommend reading this NEJM review on diuretics which can be found by googling Brater NEJM Diuretic: http://www.nejm.org/doi/full/10.1056/NEJM199808063390607

 

[deleted547339]

Tangent, but what do you do if anything for refractory 3rd spacing in the unit in a relatively normotensive patient? I was trying to look into the evidence for colloid/diuretic drip for edema in the icu and came across https://clinicaltrials.gov/ct2/show/NCT02055872 which is still recruiting. What are your thoughts on extremity wrapping? Is there any reason not to so long as the heart and kidneys alright?

Mobilization?

 

[Cytarabine]

Mobilization?

Sure, if it's a reasonable option, but in the icu population particularly in those with refractory 3rd spacing, frequently not

 

[BigRedBeta]

I think there's a weight based calculation for Lasix challenge somewhere, but on renal it seemed we'd often just go for 200 IV

Bored peds intensivist here...but in peds, we usually max out at 8mg/kg/day, but I've pushed it as high as 14mg/kg/day in the CVICU on rare occasion. I'm sure there is some theoretical limit you'd reach before that in adults. Do y'all care much about the ototoxic effects? That's usually one of the biggest things that raises eyebrows and generates phone calls from the pharmacist in my world.

Tangent, but what do you do if anything for refractory 3rd spacing in the unit in a relatively normotensive patient? I was trying to look into the evidence for colloid/diuretic drip for edema in the icu and came across https://clinicaltrials.gov/ct2/show/NCT02055872 which is still recruiting. What are your thoughts on extremity wrapping? Is there any reason not to so long as the heart and kidneys alright?

I personally don't put much faith in albumin boluses/lasix chasers and it's probably a gross oversimplification of the components of oncotic pressure and albumin metabolism. Besides, if they're 3rd spacing to that extent, I worry that their capillary leak is still significant enough that you're just going to put the albumin into the tissues and take a step back after a step forward.

 

[Brigade4Radiant]

You can get a synergistic effect by adding a thiazide diuretic to your loop diuretic if you are having difficulty in diuresing someone

 

[Cytarabine]

Bored peds intensivist here...but in peds, we usually max out at 8mg/kg/day, but I've pushed it as high as 14mg/kg/day in the CVICU on rare occasion. I'm sure there is some theoretical limit you'd reach before that in adults. Do y'all care much about the ototoxic effects? That's usually one of the biggest things that raises eyebrows and generates phone calls from the pharmacist in my world.

I'll mostly leave this to someone better informed. The nephrologists did toss it out as a "concern", but overall it didn't seem to dissuade the megadoses for challenging aki's if they thought there was a reasonable chance the patient might still be diuretic responsive. On a quick search, it looks like 240 mg/hr or 600 mg/d are adult limits

I personally don't put much faith in albumin boluses/lasix chasers and it's probably a gross oversimplification of the components of oncotic pressure and albumin metabolism. Besides, if they're 3rd spacing to that extent, I worry that their capillary leak is still significant enough that you're just going to put the albumin into the tissues and take a step back after a step forward.

Thanks. I've only seen it used once specifically to promote diuresis and it was with sequential nephron blockade (after previously being only marginally diuretic responsive) to really impressive effect. But I understand the concern with spacing the albumin itself. I imagine there's probably a subset of patients who would benefit by virtue of having "restrictive leaking" and open up enough to leak fluid but retain big protein. Not that there's a way to figure out in advance who they may be. Do you use it at all as the last option?

 

[Instatewaiter]

Bored peds intensivist here...but in peds, we usually max out at 8mg/kg/day, but I've pushed it as high as 14mg/kg/day in the CVICU on rare occasion. I'm sure there is some theoretical limit you'd reach before that in adults. Do y'all care much about the ototoxic effects? That's usually one of the biggest things that raises eyebrows and generates phone calls from the pharmacist in my world.

I think I have seen one episode of ototoxicity when the pattient was also on a concomitant aminoglycoside. Perhaps we are just missing a whole lot though. Most of our patients tend to be pretty old and kinda deaf and off balance to begin with.

For our average 100 Kg patient, 8mg/kg/day would be a massive dose of lasix for an adult- like a drip of 35 mg/h or BID dosing of 400mg which are absolutely enormous doses. When we need those kinds of doses we are adding thiazides and either moving toward UF/CVVH or adding inotropes which tend to open people up. I have rarely seen anyone give single doses north of 200mg IV x 1

 

[jdh71]

Tangent, but what do you do if anything for refractory 3rd spacing in the unit in a relatively normotensive patient? I was trying to look into the evidence for colloid/diuretic drip for edema in the icu and came across https://clinicaltrials.gov/ct2/show/NCT02055872 which is still recruiting. What are your thoughts on extremity wrapping? Is there any reason not to so long as the heart and kidneys alright?

I do use a reasonable amount of albumin with my diuretics often enough.

I've not looked into wrapping. It's not a standard practice where I work. Maybe it should be.

 

[rokshana]

I've not looked into wrapping. It's not a standard practice where I work. Maybe it should be.

my experience with wrapping was with an old school attending that LOVED Unna boots for wrapping (with surgical compression stockings over them)...but boy does it work, pretty impressively to boot...the month i was on with this attending, i think we used up all the Unna boot dressings in the VA...not standard practice because there really isn't a way to bill for it...

 

[Cytarabine]

mine experience with wrapping was with an old school attending that LOVE Unna boots for wrapping...but boy does it work, pretty impressively to boot...the month i was on with this attending, i think we used up all the Unna boot dressings in the VA...not standard practice because there really isn't a way to bill for it...

I've only seen it in one place advocated for by one fellow, but just like that attending you describe, he was SO passionate about wrapping. Just had the nurse use an ace wrap. Cheap, makes a lot of sense physiologically, certainly at least moves the fluid somewhere. But makes me raise an eyebrow that it isn't more common practice, not sure if there's more to it

 

[rokshana]

I've only seen it in one place advocated for by one fellow, but just like that attending you describe, he was SO passionate about wrapping. Just had the nurse use an ace wrap. Cheap, makes a lot of sense physiologically, certainly at least moves the fluid somewhere. But makes me raise an eyebrow that it isn't more common practice, not sure if there's more to it

i think its probably because its time consuming, and not just a simple wrap, at least with Unna boots (graduated compression with the wrap being tighter at the foot) and Unna boots are not always in stock...older PTs know how to do it, but hard to find someone to do it so you end up doing it (or teach the med students to do it...ours were well versed by the end of the rotation 🙂 ) so most people find it easier to just up the lasix (though i bet most people don't even get chance to see the wraps in the 1st place), especially if its not billable...

 

[Crayola227]

I think I have seen one episode of ototoxicity when the pattient was also on a concomitant aminoglycoside. Perhaps we are just missing a whole lot though. Most of our patients tend to be pretty old and kinda deaf and off balance to begin with.

For our average 100 Kg patient, 8mg/kg/day would be a massive dose of lasix for an adult- like a drip of 35 mg/h or BID dosing of 400mg which are absolutely enormous doses. When we need those kinds of doses we are adding thiazides and either moving toward UF/CVVH or adding inotropes which tend to open people up. I have rarely seen anyone give single doses north of 200mg IV x 1

that's what I love about peds dosing vs adult dosing

it doesn't always seem like it if you go dose for dose
but man, pound for pound those little guys sure can handle some drugs

 

[Crayola227]

i think its probably because its time consuming, and not just a simple wrap, at least with Unna boots (graduated compression with the wrap being tighter at the foot) and Unna boots are alway in stock...older PTs know how to do it, but hard to find someone to do it so you end up doing it (or teach the med students to do it...ours were well versed by the end of the rotation 🙂 ) so most people find it easier to just up the lasix (though i bet most people don't even get chance to see the wraps in the 1st place), especially if its not billable...

emphasis mine
medicine 🙁

 

[PlutoBoy]

my experience with wrapping was with an old school attending that LOVED Unna boots for wrapping (with surgical compression stockings over them)...but boy does it work, pretty impressively to boot...the month i was on with this attending, i think we used up all the Unna boot dressings in the VA...not standard practice because there really isn't a way to bill for it...

I love Unna boots 😀

 

[HelpPleaseMD]

will have to try this wrap up technique when I am back in the ICU.

 

[BigRedBeta]

that's what I love about peds dosing vs adult dosing

it doesn't always seem like it if you go dose for dose
but man, pound for pound those little guys sure can handle some drugs

Hahaha! Yeah they can...probably helps having livers and kidneys that haven't had years of abuse thrown their way.

Most of our patients tend to be pretty old and kinda deaf and off balance to begin with.

When we need those kinds of doses we are adding thiazides and either moving toward UF/CVVH or adding inotropes which tend to open people up.

That's kind of what I figured.

We're also adding thiazides at this point and our data on fluid overload in the PICU is pretty clear that early CRRT initiation has significant mortality benefit.

As for wrapping...I'd think my nurses would balk given the emphasis on pressure ulcer prevention in our unit.

 

[rokshana]

I love Unna boots 😀

Gotta admit...I do too...wished they were more available ...