Thread by @tony_breu

1/5
Why is meperidine (Demerol) particularly good at treating rigors?

This is another association I learned early in training without hearing a potential mechanism.

For the second installment in my fevers, chills, and rigors tweetorial follow-up, let's have a brief look.

2/
The ability of meperidine to treat fevers and rigors associated with amphotericin B was demonstrated in 1980 in a SMALL randomized, placebo-controlled trial.

Percent with cessation of side effects with 30 minutes:
☞ Meperidine: 100%
☞ Placebo: 30%

pubmed.ncbi.nlm.nih.gov/7362377/

3/
Meperidine is able to treat rigors (and post-anesthesia shivering) by lowering the shivering threshold.

The same temperature that would typically result in rigors isn't low enough after the use of meperidine.

pubmed.ncbi.nlm.nih.gov/9158353/

4/
The anti-shivering effect of meperidine may be related to its κ-opioid receptor activity (many opiates are pure μ-opioid receptor agonists).

This is supported by the fact that naloxone only partially blocks shivering.

pubmed.ncbi.nlm.nih.gov/8267194/

5/5
I haven't given meperidine for shaking chills, shivering, or rigors in many years.

We'll have to ask those who practice anesthesiology if it's still used post-operatively.

Is meperidine 1st line for post-op shivering, not first-line but still used, or is it avoided?

This was a second follow-up tweetorial on the topic of fevers, chills, and rigors.

Here's follow-up #1 on amphotericin B.

And here's the original tweetorial.