Important Drug Interaction in inpatient pharmacy

[skarndghks2017]

What are some important drug interaction in inpatient pharmacy setting?
I've been taught and practiced unless it's super x drug interaction like anticoagulant (ie. warfarin+apixaban), I let it go since it's acute care setting.

Also, any thoughtful interventions you guys made in inpatient setting to the doctors?

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[El Trombopag]

Carbapenems and valproate is a good one to never miss.


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[Dred Pirate]

What are some important drug interaction in inpatient pharmacy setting?
I've been taught and practiced unless it's super x drug interaction like anticoagulant (ie. warfarin+apixaban), I let it go since it's acute care setting.

Also, any thoughtful interventions you guys made in inpatient setting to the doctors?

who is telling you to just ignore drug interactions? Obviously there are some we (as in rph's) worry to much about - but that is our job?

nitrates + viagra
sotalol and/or tikosyn and a whole bunch of things
I could go one, but I am too lazy

 

[PharmDBro2017]

When I see QT interval >500, pt on amiodarone+levaquin. Seems most pharmacists I work with disregard that interaction since the pt is in the hospital and is technically being "monitored closely". They still railed us in school on that combo though.


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[Rockinacoustic]

When I see QT interval >500, pt on amiodarone+levaquin. Seems most pharmacists I work with disregard that interaction since the pt is in the hospital and is technically being "monitored closely". They still railed us in school on that combo though.


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9 times out of 10 there is no good reason to be on levaquin, QTc prolongation aside.

 

[awval999]

Cipro and Tizanide
Cipro and Cymbala
1a2 interaction. Contraindicated.

Just use Levaquin instead.

lol qtc interactions by the way. Unless it's literally something asinine like duplicate antiarrthhmics like sotalol + tikosyn.

 

[PharmDBro2017]

9 times out of 10 there is no good reason to be on levaquin, QTc prolongation aside.

It's either that or Zosyn (or they are on both for double pseudomonas cvg).

 

[skarndghks2017]

When I see QT interval >500, pt on amiodarone+levaquin. Seems most pharmacists I work with disregard that interaction since the pt is in the hospital and is technically being "monitored closely". They still railed us in school on that combo though.
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Exactly. They are on the units and monitored closely for QT interval and other possible drug interaction.
We hired a new grad and she is so concerned about drug interaction she checks like every drug interaction on lexi/micromedex so I've told her not to worry for many things and she was so shocked lol

 

[Dred Pirate]

When I see QT interval >500, pt on amiodarone+levaquin. Seems most pharmacists I work with disregard that interaction since the pt is in the hospital and is technically being "monitored closely". They still railed us in school on that combo though.


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To say they are "being monitored" as a reason for approving that combo is BS - we are monitoring them (hence we know the Qtc) and thus know we should NOT use that combo in that setting. Monitoring doesn't stop torsades from happening, just because we are watching for it, doesn't mean we can correct it if it happens.

ugh

 

[PharmDBro2017]

To say they are "being monitored" as a reason for approving that combo is BS - we are monitoring them (hence we know the Qtc) and thus know we should NOT use that combo in that setting. Monitoring doesn't stop torsades from happening, just because we are watching for it, doesn't mean we can correct it if it happens.

ugh

I agree.

It is hard because I am training right now, and the pharmacists over my shoulder say "ignore it", "they are being monitored so they're fine" "what are you going to do, not give them their amiodarone and antibiotic?"... and say to just keep verifying.

I don't want to challenge them because I'm the newbie but I'm not very comfortable with it. When I'm on my own I'll be calling to recommend abx change.

 

[Dred Pirate]

I agree.

It is hard because I am training right now, and the pharmacists over my shoulder say "ignore it" and keep verifying. I don't want to challenge them because I'm the "newbie".

Depending on your local politics at work, that can be frustrating - the older seasoned RPh's that haven't kept up with times don't seem to get it - (I am by no means lumping all odler RPh's together - some of my best RPH's are the 25+ years experience who know how to put it all together) -ultimately you have to do what you feel is right - I have been to many many codes due to torsades induced by Dofetilide +/- interacting drugs. It is nothing to take lightly -

 

[PharmDBro2017]

Depending on your local politics at work, that can be frustrating - the older seasoned RPh's that haven't kept up with times don't seem to get it - (I am by no means lumping all odler RPh's together - some of my best RPH's are the 25+ years experience who know how to put it all together) -ultimately you have to do what you feel is right - I have been to many many codes due to torsades induced by Dofetilide +/- interacting drugs. It is nothing to take lightly -

Check my post above, slightly edited it.

Also there are several that want to check vanc prior to the 3rd dose... idk about you guys but last time I checked IDSA guidelines and what I was taught, vanc troughs are done prior to the 4th or 5th dose. I prefer prior to the 4th dose. That annoys me... why get an early trough when they aren't technically at steady state?

 

[positivesign]

Check my post above, slightly edited it.

Also there are several that want to check vanc prior to the 3rd dose... idk about you guys but last time I checked IDSA guidelines and what I was taught, vanc troughs are done prior to the 4th or 5th dose. I prefer prior to the 4th dose. That annoys me... why get an early trough when they aren't technically at steady state?

For vancomycin, I think it can be tricky. If you see a big SCr jump/decrease, or pt's clinical status deteriorating overnight, or have pt who's quadriplegic so SCr is undetectable AND septic with WBC >40, I think I wanna check an early level. My rule for pulling a trigger on an early level has been

1) Is the patient likely to follow your average population PK parameters? (because that's how we got our empiric dosing)
2) How sick is this patient to make you worry if trough < 15?

But in other cases, I agree that we should wait until the presumed steady-state because the level has more predictive value.

 

[PharmDBro2017]

I understand that, and that makes sense to consider an early level in those specific cases.

But to make a blanket statement and always do vanc trough prior to the 3rd dose is what I'm facing.

 

[positivesign]

I understand that, and that makes sense to consider an early level in those specific cases.

But to make a blanket statement and always do vanc trough prior to the 3rd dose is what I'm facing.

That's pretty lame..what's their reason behind doing an early level all the time?

 

[PharmDBro2017]

That's pretty lame..what's their reason behind doing an early level all the time?

Just things like "what difference will it make between 2 and 3 doses... might as well get one now". I tried to justify doing a trough before the 4th dose (discussing steady state, what we've been taught, IDSA guidelines), etc. but they're stuck in their habits of drawing before the 3rd dose.

 

[positivesign]

Just things like "what difference will it make between 2 and 3 doses... might as well get one now". I tried to justify doing a trough before the 4th dose (discussing steady state, what we've been taught, IDSA guidelines), etc. but they're stuck in their habits of drawing before the 3rd dose.

It's tough being a new guy. I have to agree that fundamentally what we may be saying could be right, but the RPhs training us have been through much more and probably don't have ears open to hear us. I often experienced feedbacks like whatever I say sounds too "student minded, too clinical, you don't have time for that, you're not the clinical pharmacist, etc." When in fact, I've seen staff pharmacists at another hospital making those very interventions that I was suggesting....I think what I'm experiencing is a cultural difference between hospitals where one I'm from has the "hybrid model" with >95% pharmacists being residency-trained vs. one I'm at has some RPhs always doing clinical shifts and the others always doing staffing, none of them residency-trained.

 

[sosoo]

besides Qt prolongation, quinolones shouldn't be used readily to prevent CDif infection..

 

[PharmDBro2017]

besides Qt prolongation, quinolones shouldn't be used readily to prevent CDif infection..

In an ideal world, sure. Good luck getting doctors to actually follow that...

 

[bacillus1]

I shake my head every time the staff pharmacists flag clarithromycin due to drug interactions but still put through concomitant amoxicillin for H. pylori. Hello, antimicrobial resistance! Then of course there are those that put through the clarithromycin as well, ugh. Also, SQ heparin and warfarin or DOAC happens all the time.

 

[Digsbe]

I don't think I'd flag heparin and warfarin so long as there is an INR (which nearly all have).

 

[Dalteparin]

I don't think I'd flag heparin and warfarin so long as there is an INR (which nearly all have).

Say what? If the INR is therapeutic, the patient doesn't need heparin. If the patient needs to be bridged for whatever reason, SQ heparin is not recommended for that - the patient needs either LMWH or a heparin drip.

 

[sosoo]

And you should probably put when the drug actually expires on the label to prevent patients from taking expired meds....

no can do. when i come in at 9pm, theres 4 pages in qp, 4 pages in qv. the baskets are already line up. done deal. i won't know the original bottle's expiration.

 

[lane one]

Cipro and Tizanide
Cipro and Cymbala
1a2 interaction. Contraindicated.

Just use Levaquin instead.

lol qtc interactions by the way. Unless it's literally something asinine like duplicate antiarrthhmics like sotalol + tikosyn.

Lolling at QTc interactions makes you negligent imo, especially if your EMR alerted you on multiple QT agents and QTc is >500. That's a good time to rec alternatives.

 

[Dred Pirate]

Lolling at QTc interactions makes you negligent imo, especially if your EMR alerted you on multiple QT agents and QTc is >500. That's a good time to rec alternatives.

this x1000 - are pharmacists often too over the top? yes - but I have seen torsades occur then the MD note says "due to interaction of x and y", etc - so unless you want to be thrown under the bus when it does happen, intervene.

 

[Dred Pirate]

no can do. when i come in at 9pm, theres 4 pages in qp, 4 pages in qv. the baskets are already line up. done deal. i won't know the original bottle's expiration.

then you are not doing your job - you need your techs to actually respect you and do what they are told (meaning you need to tell them, which you are not)

 

[Dred Pirate]

I shake my head every time the staff pharmacists flag clarithromycin due to drug interactions but still put through concomitant amoxicillin for H. pylori. Hello, antimicrobial resistance! Then of course there are those that put through the clarithromycin as well, ugh. Also, SQ heparin and warfarin or DOAC happens all the time.

people still use clarithromycin???? I can't remember the last time I saw a patient on it -

 

[PharmDBro2017]

this x1000 - are pharmacists often too over the top? yes - but I have seen torsades occur then the MD note says "due to interaction of x and y", etc - so unless you want to be thrown under the bus when it does happen, intervene.

What are your thoughts on new admit with warfarin home med and being started on amiodarone?

 

[Dred Pirate]

In an ideal world, sure. Good luck getting doctors to actually follow that...

I probably get a MD to change from levo to keflex (or rocephin if needs IV) at least once a week (usually more) when treating a uncomplicated UTI

 

[Dred Pirate]

What are your thoughts on new admit with warfarin home med and being started on amiodarone?

cut the warfarin dose in in half (provided they are currently therapeutic) - and monitor with daily INR's


I miss actually talking pharmacy clinical stuff on here

 

[PharmDBro2017]

I probably get a MD to change from levo to keflex (or rocephin if needs IV) at least once a week (usually more) when treating a uncomplicated UTI

For uncomplicated UTI, that is reasonable (the newest recommendations say no fluoroquinolones for uncomplicated UTI iirc)

But suspected HAP empirically treating and QT >500, recommend cefepime (D/C levaquin and start cefepime instead)? Do you even worry about QT if it's <500?

 

[Dred Pirate]

For uncomplicated UTI, that is reasonable (the newest recommendations say no fluoroquinolones for uncomplicated UTI iirc)

But suspected HAP empirically treating and QT >500, recommend cefepime (D/C levaquin and start cefepime instead)? Do you even worry about QT if it's <500?

yes - two different scenarios - our levo resistence rate to e coli is 25% and growing.

HAP - correct me if I am wrong - but our options are levo or rocephin + azithro - azithro is no better qtc wise. (now that I type this that is CAP) - I need my cheat sheet as I am having a brain fart - but I am thinking normally HAP is vanc + levo + zosyn - sub doxy if QTC is elevated. (I am pulling this from my sepsis with source as PNA memory)

I start to worry when it is 480 or greater. I often will let it slide up to 500 if we are monitoring, but keep an eye on it. A lot depends on if we are adding anything else, pt's history, etc

 

[PharmDBro2017]

yes - two different scenarios - our levo resistence rate to e coli is 25% and growing.

HAP - correct me if I am wrong - but our options are levo or rocephin + azithro - azithro is no better qtc wise. (now that I type this that is CAP) - I need my cheat sheet as I am having a brain fart - but I am thinking normally HAP is vanc + levo + zosyn - sub doxy if QTC is elevated. (I am pulling this from my sepsis with source as PNA memory)

I start to worry when it is 480 or greater. I often will let it slide up to 500 if we are monitoring, but keep an eye on it. A lot depends on if we are adding anything else, pt's history, etc

Correct, vanc +levaquin + zosyn for HAP. Didn't think about doxy, but I was assuming for double pseudomonas cvg to use cefepime (rather than levaquin [for QT]).

Also that warfarin pt had INR of like 1.2 or 1.4 iirc... pharmacist just told me to verify it.

 

[Dred Pirate]

Correct, vanc +levaquin + zosyn for HAP. Didn't think about doxy, but I was assuming for double pseudomonas cvg to use cefepime (rather than levaquin [for QT]).

Also that warfarin pt had INR of like 1.2 or 1.4 iirc... pharmacist just told me to verify it.

don't add cefepime to zosyn - double beta lactams actually perform worse than each agent alone due to competitive binding at the beta lactam binding site on the bacteria - basically competitive antagonism.

You can argue the merits of double coverage of pseudomas - I was taught to always double cover - but that was 10+ years ago - in that situation aminoglycosides are you only real option - and the benefits vs risks often lean towards no.

in that warfarin pt - yes - I would verify it - doubling the INR would be a good thing (and bridge with LMWH if appropriate).

 

[PharmDBro2017]

Man total brain fart there about doubling beta lactams, good lord. Studying and working all day has fried my brain.

Thanks for the tips.

 

[bacillus1]

people still use clarithromycin???? I can't remember the last time I saw a patient on it -

H. pylori. Both the triple and quadruple clarithromycin-based regimens are much cheaper than Pylera.

 

[skarndghks2017]

man.. I am glad I asked the question.
I am learning so much from this post. You see, it's important to learn appropriately.
I work in a small hospital and got training by pharmacists who don't think like this.
For the past 3 years, I have NOT checked many of drug interactions discussed here....
I need to brush up my clinical knowledge again...

 

[PolarPop]

Man total brain fart there about doubling beta lactams, good lord. Studying and working all day has fried my brain.

Thanks for the tips.

You can use aztreonam to double cover though if other options aren't available.

We give dual beta lactams sometimes but only for meningitis, enterococcal endocarditis, and for serious MSSA infections where you can't really d/c the oxacillin. The actual data to support beta lactam antagonism in general is almost nonexistent but everyone will tell you never to do it. We had a patient on oxacillin+ceftazidime once and I got a call every other day for 2 weeks from different pharmacists that the patient was going to have a seizure and die or that it's just weird.

 

[Rockinacoustic]

You can use aztreonam to double cover though if other options aren't available.

We give dual beta lactams sometimes but only for meningitis, enterococcal endocarditis, and for serious MSSA infections where you can't really d/c the oxacillin. The actual data to support beta lactam antagonism in general is almost nonexistent but everyone will tell you never to do it. We had a patient on oxacillin+ceftazidime once and I got a call every other day for 2 weeks from different pharmacists that the patient was going to have a seizure and die or that it's just weird.

Dual beta-lactams for meningitis are targeting different bacterial species though. Ampicillin and Ceftriaxone synergy for enterococcal endocarditis is the only evidence-based combination of beta-lactams I'm aware of.

Until there's literature to support it I can't imagine a scenario where I'd be adding aztreonam to a beta-lactam backbone for a suspected MDRO infection.

 

[PolarPop]

There is, mostly for MBL producing gram-negatives but it is there. It's also literally written in the IDSA guideline.

 

[Rockinacoustic]

There is, mostly for MBL producing gram-negatives but it is there. It's also literally written in the IDSA guideline.

Interesting. I'll have to check this out and hope to never see these organisms at my institution

 

[PolarPop]

Interesting. I'll have to check this out and hope to never see these organisms at my institution

You never know with the way things are going these days

 

[Dred Pirate]

H. pylori. Both the triple and quadruple clarithromycin-based regimens are much cheaper than Pylera.

I really haven't seen traditional H pylori treatment recently - the last time I did - I had a patient on pylera - we changed to:
Bismuth subsalicylate, metronidazole, tetracycline, + a PPI as individual ingredients - pretty cheap

 

[bacillus1]

I really haven't seen traditional H pylori treatment recently - the last time I did - I had a patient on pylera - we changed to:
Bismuth subsalicylate, metronidazole, tetracycline, + a PPI as individual ingredients - pretty cheap

Have you been able to get tetracycline lately? Thought it was on backorder. Could also just be our supplier though.

 

[PharmDBro2017]

One of the contraindications that was harped on in school was use of ACE/ARB + Aliskiren since they are both essentially doing the exact same thing (RAAS pathway, just slightly different MOA with renin/angiotensin). You guys ever see patients on both? It doesn't make since why someone would be on both imo, but I saw it the other day.

 

[Rockinacoustic]

One of the contraindications that was harped on in school was use of ACE/ARB + Aliskiren since they are both essentially doing the exact same thing (RAAS pathway, just slightly different MOA with renin/angiotensin). You guys ever see patients on both? It doesn't make since why someone would be on both imo, but I saw it the other day.

They took Valturna off the market for a reason.

 

[owlegrad]

One of the contraindications that was harped on in school was use of ACE/ARB + Aliskiren since they are both essentially doing the exact same thing (RAAS pathway, just slightly different MOA with renin/angiotensin). You guys ever see patients on both? It doesn't make since why someone would be on both imo, but I saw it the other day.

I did an APPE presentation on this exact topic after seeing the combination at my community APPE. Since that time I do not recall seeing the combination again. I rarely see a prescription for Aliskiren at all though, in fact I am not even sure I recall the last time I dispensed it.

 

[Dalteparin]

this x1000 - are pharmacists often too over the top? yes - but I have seen torsades occur then the MD note says "due to interaction of x and y", etc - so unless you want to be thrown under the bus when it does happen, intervene.

Agreed. I actually had a patient come to the hospital in cardiac arrest after experiencing drug-induced torsades. This is not something to mess around with.

 

[Dred Pirate]

Agreed. I actually had a patient come to the hospital in cardiac arrest after experiencing drug-induced torsades. This is not something to mess around with.

my record is a qtc of 750 - went home on levaquin, acute renal failure (not sure of srcr - received levo at another institution) - in out of arrest for 1.5 hours or so - eventually expired.

 

[Dred Pirate]

Have you been able to get tetracycline lately? Thought it was on backorder. Could also just be our supplier though.

we don't carry it on formulary - now that I think of it, I think I switched to doxy while they were in the hospital.