Zofran potentiates opiates?

Sublime

Sublime

LP, RN
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So at my nursing clinical the other day my instructor started talking about Zofran potentiating narcotics such as morphine. I've never heard this. I'm well aware of phenergan and it's narcotic potentiating effects, but hadn't heard that about Zofran. I did my research and found nothing on zofran potentiating opiates.

Does anyone know of any evidence of this?
 
I've never heard of it either. I think your instructor may have just been confusing the two antiemetics...
 
Definitely wasn't confusing them as she mentioned phenergan also. Perhaps she assumed that since phenergan did than so did zofran. But not five minutes later she was lecturing a student on pulse points correlating with systolic blood pressure minimums (if you can feel a femoral it's at least 60-90 or whatever) so clearly not everything she is teaching is based on clear evidence.
 
The only thing I have heard about Zofran is that it can, in very high doses, cause QT prolongation as well as potentiate QT prolongation when used with Sotalol, Haldol, congenital long QT, or electrolyte imbalances.

IRRC it took 32mg of Zofran to create clinically significant QT prolongation in normal patients.
 
http://www.sciencedaily.com/releases/2009/02/090217212255.htm

Zofran specifically blocks 5-HT3 receptors so it masks opioid withdrawal.
I can see where, as the opioid wears off, the tail end of analgesia not being overwhelmed by withdrawl s/s would seem like a prolongation of opioid action, when it is simply disguising the jitters, N/V/D.

Sidebar.

We had MD's who prescribed Lomotil, a scheduled controlled antidiarrheal, PRN for withdrawing heroin addicts. You can bet those guys c/o lots of diarrhea, for weeks. Immodium, in high enough doses, is also a narcotic.
 
Chase said:
The only thing I have heard about Zofran is that it can, in very high doses, cause QT prolongation as well as potentiate QT prolongation when used with Sotalol, Haldol, congenital long QT, or electrolyte imbalances.

IRRC it took 32mg of Zofran to create clinically significant QT prolongation in normal patients.
Click to expand...

Zofran actually causes more qt prolongation than either promethazine or droperidol.
 
That's 1980's.
 
Chase said:
The only thing I have heard about Zofran is that it can, in very high doses, cause QT prolongation as well as potentiate QT prolongation when used with Sotalol, Haldol, congenital long QT, or electrolyte imbalances.

IRRC it took 32mg of Zofran to create clinically significant QT prolongation in normal patients.
Click to expand...

I point that out on a daily basis and people still insist that I'm wrong even when I pull up the study.

"You need to be careful even at 4 mg! I don't give it if they're throwing ectopy to avoid the R-on-T phenomenon!"
 
Robb said:
I point that out on a daily basis and people still insist that I'm wrong even when I pull up the study.

"You need to be careful even at 4 mg! I don't give it if they're throwing ectopy to avoid the R-on-T phenomenon!"
Click to expand...

Although do know that syncopal episodes occur at normal dosages if you push it too quickly.
 
Wait wait wait... Imodium can get you HIGH??? Brb... I think I won't be pooping for the next month....
 
MIx it with Exlax.
 
mycrofft said:
MIx it with Exlax.
Click to expand...

Haha, that's great! Senna would also work...

On a side note, I was under the impression that loperamide (Immodium) worked as an opioid receptor agonist that was too hydrophilic / lipophobic to cross the BBB. Mixing it with something to act as a carrier protein or increase its affinity for lipids would make sense to get the opiate properties... Wouldn't taking it in excess do nothing for getting it to the target receptors? Unless a small amount already crosses the BBB, and by increasing dosage you'd also increase the amount that hits CNS receptors? Where is Goodman and Gilman when you need them?
 
Use Google Scholar to look up whether promethazine actually potentiates opiate. The results will likely be surprising....
 
usalsfyre said:
Use Google Scholar to look up whether promethazine actually potentiates opiate. The results will likely be surprising....
Click to expand...

Not much on the subject since the 70's, and most say it "potentiates" by slowing the removal of opiates by the liver... that being said, phenothiazine derivatives have some pretty strong effects on their own.

The following table illustrates this nicely:
phenergan-50-table.png
 
NIH article for laypersons. LOTS of drug interactions.
http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601209.html
Doesn't mention narcotics of any sort, maybe they are "other". ?

I'm not finding anything about prolonging action of narcotics, just that it masks s/s of withdrawl so the upward curve of detox discomfort isn't there to mask the last of the downward curve of analgesia. The subjective difference is nil (other than no detox s/s), but it should not prolong the objective activity (vital signs, labs).
 
I don't have anything to cite that hasn't already been listed here, but I can confirm that several of the docs I deal with routinely push zofran with morphine/opiates as a standard precaution against nausea side effects.
 
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