Some more clinical questions pt.2

[GravityBeetle]

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Thanks to all who replied to my previous thread. I learned a lot from your different perspectives. Here's another set of questions from issues I've encountered:

1. How do you deal with timing of different antibiotics peri-operatively? For example: pregnant female comes in for a C-section. She gets penicillin G q4h, then cefazolin once for incision, then ampicillin q6h postpartum for intra-amniotic infection. That's a ton of beta-lactams within a 24h period. Would you try to space those out in any certain way?
2. Thoughts on macrobid vs bactrim for UTIs in the elderly with impaired renal function? Bactrim is contraindicated in CrCL<15 and macrobid contraindicated in CrCL<30. That means that macrobid has higher propensity to be toxic right? On the other hand i've also cases of Bactrim causing sharp rises in SCr so I'm assuming it's more nephrotoxic? Let's say patient is borderline at CrCL=31 and monurol is n/a.
3. Thoughts on what the best muscle relaxant is for the elderly? Most are on Beer's List. One that isn't is Tizanidine, but I believe that it is the most sedating one isn't it? Baclofen is another one not on Beer's list but limited to use in muscle spasticity and wonder how effective it is?

 

[confettiflyer]

1) no, baby time is baby time, and I’m not particularly concerned with beta lactam overdose in periop settings with patients in their 20s-30s.

2) I’d probably dose macrobid when crcl 31, that’s a win in my book

3) I’ll let someone from the am care world chime in on this one

 

[pharmer747]

1. Ill let someone from surgery answer that

2. For SMX-TMP I was always taught that it causes artificial rises in SCr that are not related to renal function. Although it does cause increased K and you gotta be careful with pts on Ace/Arbs.

3. No clue

 

[zelman]

3. Your instincts are good. Zanaflex and Lioresal are probably the best options when direct heat is not sufficient therapy. Basically, avoid Soma like crazy and Flexeril isn’t such a great idea either. Everything else is a possible option, but the two you chose are going to have the best adverse effect profiles. I’d say Skelaxin is the next best option, but might want to dose conservatively (split the 800mg tabs since they don’t make the 400’s anymore).

 

[sakigt]

Tizanidine is the only one with a MOA that could actually do anything for the muscles

 

[rxkrafted]

1. https://www.ashp.org/-/media/assets...elines-antimicrobial-prophylaxis-surgery.ashx
see page 656. If the scenario was for just prophylactic abx for surgery, then I would just make sure the last antibiotic gets administered within the 24 hours after surgery end time to meet the SCIP quality core measure that our hospital has to follow for Joint Commission.

2. I agree with what everyone else said. It is also important to note that Macrobid is bacteriostatic in most cases.

3. Not sure but they will have all some degree of sedation so all will generally be used cautiously in elderly. You are correct, most are on the Beer's list because of this. I would probably look into Zelman's recommendation.

 

[GravityBeetle]

3. Your instincts are good. Zanaflex and Lioresal are probably the best options when direct heat is not sufficient therapy. Basically, avoid Soma like crazy and Flexeril isn’t such a great idea either. Everything else is a possible option, but the two you chose are going to have the best adverse effect profiles. I’d say Skelaxin is the next best option, but might want to dose conservatively (split the 800mg tabs since they don’t make the 400’s anymore).

Tizanidine is the only one with a MOA that could actually do anything for the muscles

Isn't Tizanidine the most sedating though? More so than Flexiril at least?

1) no, baby time is baby time, and I’m not particularly concerned with beta lactam overdose in periop settings with patients in their 20s-30s.

2) I’d probably dose macrobid when crcl 31, that’s a win in my book

3) I’ll let someone from the am care world chime in on this one

1. https://www.ashp.org/-/media/assets...elines-antimicrobial-prophylaxis-surgery.ashx
see page 656. If the scenario was for just prophylactic abx for surgery, then I would just make sure the last antibiotic gets administered within the 24 hours after surgery end time to meet the SCIP quality core measure that our hospital has to follow for Joint Commission.

2. I agree with what everyone else said. It is also important to note that Macrobid is bacteriostatic in most cases.

3. Not sure but they will have all some degree of sedation so all will generally be used cautiously in elderly. You are correct, most are on the Beer's list because of this. I would probably look into Zelman's recommendation.

1. Ill let someone from surgery answer that

2. For SMX-TMP I was always taught that it causes artificial rises in SCr that are not related to renal function. Although it does cause increased K and you gotta be careful with pts on Ace/Arbs.

3. No clue

What if the crcl is slightly below 30? Macrobid is then contraindicated so that leaves us with bactrim...would you be worried of nephrotoxicity? Let's assume they're allergic to penicillins, would you just choose an FQ with renal adjustments?

 

[rxkrafted]

What if the crcl is slightly below 30? Macrobid is then contraindicated so that leaves us with bactrim...would you be worried of nephrotoxicity? Let's assume they're allergic to penicillins, would you just choose an FQ with renal adjustments?

If the CrCl is slightly below 30, I would recommend other alternatives if possible. No, I would not be worried about nephrotoxicity as long as it is dose-adjusted for given CrCl and above the cutoff for contraindication. We are encouraged to avoid FQs for uncomplicated UTIs but if no alternatives exist, yeah go for it.

 

[Rockinacoustic]

What if the crcl is slightly below 30? Macrobid is then contraindicated so that leaves us with bactrim...would you be worried of nephrotoxicity? Let's assume they're allergic to penicillins, would you just choose an FQ with renal adjustments?

I typically talk to them and find out their penicillin "allergy" is vague or not an allergy at best and can safely prescribe a cephalosporin.

I would do all I can to avoid FQ in elderly with poor renal function. Bactrim is much easier to dose adjust and has less potential for collateral damage in their 3 days of treatment.

 

[zelman]

Isn't Tizanidine the most sedating though? More so than Flexiril at least?

Definitely not. Flexeril’s structure puts it in the TCA class.

 

[pharmBear]

Finally a fun clinical discussion.

1. No personal experience, but given the high antibiotic resistance risk, the time above the mic is so so important.

2. Look at the patient as a whole when picking your regimen. In the hospital setting there are protocols to follow.

3. This is a current issue in practice with the new beers guideline. In general, tizanidine tabs and baclofen tabs are generally equally efficacious in practice. The high risk muscle relaxers such as methocarbamol are being prior auth in favor of less risk baclofen and tizanidine ( again the tablet version).

Good questions

 

[bacillus1]

1) no, baby time is baby time, and I’m not particularly concerned with beta lactam overdose in periop settings with patients in their 20s-30s.

2) I’d probably dose macrobid when crcl 31, that’s a win in my book

3) I’ll let someone from the am care world chime in on this one

Depends on patient's gender. There was a study of macrobid showing that it does not work in men in CrCl<60 for gram-negative infections, while renal function has to be pretty much perfect for gram-positive infections.