UDS positive for PCP

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sevo00

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Would you all cancel a total hip replacement for a UDS positive for PCP?
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What exactly is the positive drug test? Cocaine? Even positive cocaine means little these days as long as more than 8 hours from last use and symptoms.
 
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sevo00 said:
Not cocaine positive for PCP
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Couple of things you can do.

If they are acting strangely definitely consider cancelling.

Another trick question I do is simply ask them how long as last time they used pcp. If they say a couple of months ago. They are lying. I’d just cancel them not for the pcp. But for the lies.

If they are up front and said they used it last few days. I’d let them slide.
 
Why was the UDS run in the first place? Anything else light up?

I haven't seen it happen in at least a year or two, but I had a string of people in my ICU with everything negative on the UDS, except PCP. Within 24hrs, the lab quietly changed them all to negative results. Made for some awkward conversations with patients.
 
psychbender said:
Why was the UDS run in the first place? Anything else light up?

I haven't seen it happen in at least a year or two, but I had a string of people in my ICU with everything negative on the UDS, except PCP. Within 24hrs, the lab quietly changed them all to negative results. Made for some awkward conversations with patients.
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Patient had a previous Uds positive for pcp so that’s why the team decided to run another one preop.
 
If they are clear headed and not acutely intoxicated, is there an anesthetic indication to cancel for a positive UDS? I would leave it up to the surgeon because there could be postop followup and compliance issues. If they’re injecting, they’re at risk for prosthetic joint infection.

If the surgeon gives the green light, you could premedicate with ketamine and wait for the five star Yelp review😉
 
www.ncbi.nlm.nih.gov

How Often Do False-positive Phencyclidine (PCP) Urine Screens Occur with Use of Common Medications?

Previous reports describe false positive urine immunoassay screens for phencyclidine (PCP) associated with use of tramadol, dextromethorphan, or diphenhydramine. The likelihood of these false positives is unknown.We sought to find the relative frequency ...
www.ncbi.nlm.nih.gov www.ncbi.nlm.nih.gov

pubmed.ncbi.nlm.nih.gov

False-positive phencyclidine (PCP) on urine drug screen attributed to desvenlafaxine (Pristiq) use - PubMed

We report a likely false-positive phencyclidine (PCP) result detected with a urine drug screen (UDS) (Medtox, St Paul, Minnesota, USA) in the setting of therapeutic desvenlafaxine (Pristiq) use. Desvenlafaxine (O-desmethylvenlafaxine) is the active metabolite of venlafaxine (Effexor). Prior...
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov

I think PCP on the UDS has one of the highest false-positive/cross-reactivity rates, if I remember correctly?
 
aneftp said:
What exactly is the positive drug test? Cocaine? Even positive cocaine means little these days as long as more than 8 hours from last use and symptoms.
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And you're going to believe a drug user when they tell you they didn't use cocaine in the last 8 hours?

Positive cocaine or meth = cancel anything elective

No need to even talk to the patient, beyond relaying the news. Don't care what they say about symptoms or last use.
 
pgg said:
And you're going to believe a drug user when they tell you they didn't use cocaine in the last 8 hours?

Positive cocaine or meth = cancel anything elective

No need to even talk to the patient, beyond relaying the news. Don't care what they say about symptoms or last use.
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No. I ask the drug user when the last time they use cocaine. Knowing full well it should be out of their system in 3-4 days.

If they tell me it’s been a couple of months. It’s a lie as we all know.

Studies have shown if patients show no objective signs like increased bp, tachycardia. U can proceed with cocaine use and considering these “elective” positive drug tests patients are more than 8 hours npo. It’s ok to proceed.

There was Australian article about cocaine also. Bigger study.
But only one I can find than morning is British study

 
psychbender said:
Why was the UDS run in the first place? Anything else light up?

I haven't seen it happen in at least a year or two, but I had a string of people in my ICU with everything negative on the UDS, except PCP. Within 24hrs, the lab quietly changed them all to negative results. Made for some awkward conversations with patients.
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OMG, this is so messed up. Did you ask the lab what happened?
 
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aneftp said:
No. I ask the drug user when the last time they use cocaine. Knowing full well it should be out of their system in 3-4 days.

If they tell me it’s been a couple of months. It’s a lie as we all know.

Studies have shown if patients show no objective signs like increased bp, tachycardia. U can proceed with cocaine use and considering these “elective” positive drug tests patients are more than 8 hours npo. It’s ok to proceed.

There was Australian article about cocaine also. Bigger study.
But only one I can find than morning is British study

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That's a fair approach.

I'll still cancel them all. Nothing they say can really be trusted. There's no up side to proceeding.
 
If they had a previous positive test and now you run a UDS pre surgery because they were previously positive, you’ve got to cancel. It would have been acceptable to proceed without the test, but once you’ve chosen to run it, you need to make a decision based on the results.
 
I'll be honest. Maybe because drug use is so rampant where I trained, but I don't think I'd ever cancel unless they seemed acutely intoxicated or had signs of it in their system currently (HTN, tachycardia). I'd have a detailed discussion about their drug use, frequency, etc, inform the surgeon in case they want to cancel, and then run with it if I don't get the impression that they have it flowing through their system currently.

The fact that people would cancel based on a positive drug screen alone actually surprised me.
 
Anyone know if a single dose of IV ephedrine will cause a positive UDS? Would it be specific for methamphetamines vs just amphetamines?
 
makemoney2024 said:
OMG, this is so messed up. Did you ask the lab what happened?
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That those were all false positives. I was more annoyed by the fact that they silently amended the read a day later, with no call or notation in the chart about the initial false positive.
 
pgg said:
That's a fair approach.

I'll still cancel them all. Nothing they say can really be trusted. There's no up side to proceeding.
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This is like saying that you can't trust that any fat person is NPO even though they claim to be NPO x 12 hours. Cancel due to aspiration risk.
 
Don’t order drug tests on elective cases unless you are committed to canceling the case if it pops positive. The worst is when the surgeon orders it and then pressures you to proceed on a positive result (by somehow explaining it away). In that case the only thing the test did was increase your liability. No thanks.
 
psychbender said:
That those were all false positives. I was more annoyed by the fact that they silently amended the read a day later, with no call or notation in the chart about the initial false positive.
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Dude, I am sorry. That is so messed up. They made you look stupid.
 
abolt18 said:
This is like saying that you can't trust that any fat person is NPO even though they claim to be NPO x 12 hours. Cancel due to aspiration risk.
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Yah, this is actually not the same thing at all. Nope. Nope. Nope. You can be fat from overeating bad food at a scheduled interval. You don't have to eat ALL THE TIME to be fat. Just eating calorie dense food and too much of it is what leads to most obesity.
Drug addicts are known to constantly lie.
 
abolt18 said:
This is like saying that you can't trust that any fat person is NPO even though they claim to be NPO x 12 hours. Cancel due to aspiration risk.
Click to expand...

Not at all. I've seen wild hemodynamic instability in meth users. Not in cocaine users but I've heard the tales.

There's degree of unreliability in drug users that makes me distrustful of their claims of last use.

Surgeons are very, very rarely unhappy when I cancel an active drug user. They tend to be high maintenance, unreliable patients with disproportionately bad outcomes because they keep doing dumb stuff.

nimbus said:
Out of curiosity, would anybody cancel for a UDS positive for THC?
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No. Meth and cocaine are the only drugs I really care about in terms of periop risk.
 
pgg said:
Not at all. I've seen wild hemodynamic instability in meth users. Not in cocaine users but I've heard the tales.

There's degree of unreliability in drug users that makes me distrustful of their claims of last use.

Surgeons are very, very rarely unhappy when I cancel an active drug user. They tend to be high maintenance, unreliable patients with disproportionately bad outcomes because they keep doing dumb stuff.



No. Meth and cocaine are the only drugs I really care about in terms of periop risk.
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If there is no drug screen, and your patient tells you outright "yeah I use Meth and/or cocaine from time to time. Last use was a few days ago" are you going to cancel that too?
 
makemoney2024 said:
Yah, this is actually not the same thing at all. Nope. Nope. Nope. You can be fat from overeating bad food at a scheduled interval. You don't have to eat ALL THE TIME to be fat. Just eating calorie dense food and too much of it is what leads to most obesity.
Drug addicts are known to constantly lie.
Click to expand...

Yeah, and you don't have to use drugs ALL THE TIME to be a drug user. Some of them actually just use it on occasion or when it's conveniently available.

I have found drug addicts to lie no more than any other human beings when you just have a genuine conversation and tell them these things matter so I can safely take care of them (unless they're lying to get their next fix).
 
DocMcCoy said:
what if admitted use day of surgery?
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If they just did it right before walking into the hospital, it's gotta cancel just due to consent issues. If they smoked this morning and now it's 4pm and they seem completely normal, proceed. In between those two situations, gotta play it by ear and assess on an individual basis. Consent capacity is my biggest concern.
 
abolt18 said:
If they just did it right before walking into the hospital, it's gotta cancel just due to consent issues. If they smoked this morning and now it's 4pm and they seem completely normal, proceed. In between those two situations, gotta play it by ear and assess on an individual basis. Consent capacity is my biggest concern.
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I feel like I've changed my practice quite a bit on this and I don't disagree with the reasoning. I just don't know how you could defend a bad outcome if its basically your word against the patient in court whether or not they were "high". Same day to me would still be a cancel. Though I recognize some everyday users get pretty anxious when they have to go without.
 
psychbender said:
Why was the UDS run in the first place? Anything else light up?

I haven't seen it happen in at least a year or two, but I had a string of people in my ICU with everything negative on the UDS, except PCP. Within 24hrs, the lab quietly changed them all to negative results. Made for some awkward conversations with patients.
Click to expand...
I was thinking something like this. I have to imagine the number of people out there who use PCP, and *only* PCP, is pretty minuscule.

We had a similar issue with our lab when in residency and some cross reactivity with MDMA on the UDS and some common drug used in elderly patients.
 
abolt18 said:
Yeah, and you don't have to use drugs ALL THE TIME to be a drug user. Some of them actually just use it on occasion or when it's conveniently available.

I have found drug addicts to lie no more than any other human beings when you just have a genuine conversation and tell them these things matter so I can safely take care of them (unless they're lying to get their next fix).
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Ok. I call BS. Drug users lie A LOT. But let’s agree to disagree. Your comparisons suck.
 
Blockit said:
Hahahaha…I wouldn’t be doing many cases if I did!
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I think it’s wild how accepted THC is and how rapidly this happened. Everyday I get patients that use some form of marijuana day of surgery and no one really blinks an eye…they still get their surgery. However if I slammed a sixer of busch lattes in the parking lot before surgery, social workers wouldn’t let me leave without an addiction consult and a rehab facility lined up.
 
Give him ketamine. Seriously, who cares. So long as the patient is lucid and consent able I would proceed. If the surgeon is concerned about possible joint infection from IVDA that is a surgical cancellation, not mine.
 
Every positive PCP I saw on POC UDS came back negative on confirmatory mass spect. I doubt they ordered the expensive send out and you’re probably looking at the false positive POC result.

IMG_0195.jpeg
 
Proceed if not acutely intoxicated and appears to be consentable. If any concern about consentability, cancel. Don't overthink it. Don't check a UDS next time. Over half our patients will have a +UDS on day of surgery.
 
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