Vertigo: FOAM, resources, and more on meclizine

Listed below are some great podcasts, papers and posts regarding vertigo.

Some good ol’ non-foam sources:

Paper from Dr. Newman-Toker – Misdiagnosing Dizzy Patients: Common Pitfalls in Clinical Practice http://www.sciencedirect.com/science/article/pii/S073386191500033X (HT Ameen)

I believe more and more doctors are beginning to appreciate that asking “is the room spinning or are you spinning” is a useless question. The TiTrate approach goes beyond these questions and presents an evidence based approach dictated by the timing and triggers rather than subjective recall of an unclear sensation.

TiTrATE: A Novel, Evidence-Based Approach to Diagnosing Acute Dizziness and Vertigo https://www.ncbi.nlm.nih.gov/pubmed/26231273

Podcasts:

EMCRIT – an older podcast from 2010 with an interview with Dr. Newman-Toker about the HINTS exam and how to distinguish between vertigo and posterior circulation stroke. A very important point is the limited sensitivity of MRI in the first 24-48 hours. http://emcrit.org/podcasts/posterior-stroke/

FOAMCAST – Solid review of vertigo as well as review of the above podcast and the EM lit of Note Post we will list below.  Listed in the show notes are some very important limitations of the HINTS exam (has not been validated when performed by ED or IM physicians) http://foamcast.org/2016/01/12/episode-41-vertigo/

 

On meclizine:

EM lit Of Note – whats the big deal about meclizine.

Ryan Radecki did a brief lit review and found very little support for the use of meclizine for vertigo. He endorses Phenergan based on the study he discusses in the post. Please see the post for details (http://www.emlitofnote.com/?p=3192) I would note, however, that the study was specifically looking at motion sickness and not vertigo.

Per uptodate.com, meclizine is preferred in pregnancy and Phenergan is more sedating so they reserve it for vomiting patients (in which case the rectal form can be useful as Dr. Radecki points out).

I tried to see if there was any better evidence for meclizine. (the review article I had read simply said “there are no RCTs”). Since I did not think that I would do a better job than Ryan Radecki, I cheated and tracked back the source of uptodates recommendation. Their source recommending either antihistamines, benzos or antiemetics was based on a 1992 article from the journal “Drugs” called   “pharmacologic agents affecting emesis” http://link.springer.com/article/10.2165%2F00003495-199243030-00002 . As you can easily appreciate from the title of the article the focus is on emesis and not decreasing the vertiginous sensation. 

Per the paper:

“Several H I-receptor antagonists are effective in treating vomiting due to motion sickness and other labyrinthine disturbances (e.g. Meniere’s disease), as well as pregnancy, uraemia and postoperative vomiting. ”  It is not immediately clear from the article what the source for this statement was. A few sentences later they quote Chinn et. al. 1950 as a source that some potent h1 blockers are not effective. I tried to access this paper and found 3 publications by HI Chinn in 1950 all exploring motion sickness. I did not have access to any of these papers (they do not appear to be available online) and thus I hit the bottom of my rabbit hole. (https://www.ncbi.nlm.nih.gov/pubmed/14777196 , https://www.ncbi.nlm.nih.gov/pubmed/14778797 , https://www.ncbi.nlm.nih.gov/pubmed/14776687 )

It is interesting to note that these papers seem to address motion sickness prophylaxis (not emesis per se, and not specifically vertigo). Regardless of the content of the papers, since this is addressing motion sickness (and not vertigo or emesis) we can go back to the paper quoted in Dr. Radeckis post as perhaps the most relevant and authoritative.

The one RTC ( albeit small n=20) looking at an antihistamines effect on motion sickness and vestibular ocular reflex quoted in the above article was actually a negative study. https://www.ncbi.nlm.nih.gov/pubmed/3122717

Bottom line; meclizine for vertigo seems to be poorly supported by medical evidence but has likely been more of an expert opinion which has been passed down for 65 years and became dogma.

I will keep the discussion to vertigo and not delve into true syncope since the PESIT trial has already been extensively covered in the foam world; foamcast ,rebelem , emnerd. I will note that the trial only included patients with true syncope (they passed out) and did not include presyncope and/or dizzy patients.

 

please contact me @foamflea with any comments

 

 

 

 

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