The “pink lady” or “GI cocktail”, a combination of an antacid and viscous lidocaine, is both much loved and much hated in emergency medicine. Some practitioners use it as a matter of routine. Others warn against it, for fear that it can lead to misdiagnosis in the setting of MI. (As an aside, please let me know if you are aware of the studies that led to the common teaching that the pink lady leads to misdiagnosis in the setting of ACS. I started looking, and the only citation I could find was Wrenn 1995, in which they say “eight (73%) of eleven patients admitted for possible myocardial ischemia were noted to have some degree of relief after the GI cocktail.” (Wrenn 1995) That is far from definitive. The patients only had “possible” MI, and we are given no further details.) However, the primary question for this post is: does a pink lady provide any more pain relief than an antacid alone?
Berman DA, Porter RS, Graber M. The GI Cocktail is no more effective than plain liquid antacid: a randomized, double blind clinical trial. The Journal of emergency medicine. 2003; 25(3):239-44. PMID: 14585449
This is a single centre, double-blind, randomized controlled trial.
A convenience sample of adult patients with dyspepsia for whom the emergency doctor ordered a “GI cocktail”.
- Exclusions: Suspected cardiac or pulmonary etiology (including patients receiving any cardiovascular medications in the ED), pregnancy, oral warfarin therapy, active GI bleeding (other than heme-positive stool), incompetence to consent, and self-administration of antacid within 1 h.
Interventions and Comparison
Group 1: 30 mL of Mylanta (a combination of magnesium hydroxide, aluminium hydroxide, and simethicone)
Group 2: 30 mL of Mylanta plus 10mL of Donnatal (a combination of phenobarbital, hyoscyamine sulfate, atropine sulfate, and scopolamine hydrobromide, meant to act as an antispasmodic and anticholinergic agent)
Group 3: 30 mL of Mylanta plus 10mL of Donnatal plus 10 mL of 2% viscous lidocaine
The primary outcome was relief of pain (as measured by the difference in millimeters between the pretreatment and posttreatment visual analog scales) at 30 minutes. A 13 mm (out of 100) difference was considered clinically significant.
They enrolled 120 patients over a 6 month period, and 113 completed the protocol.
The mean decrease in pain was:
- Group 1: 25mm +/- 27mm (standard deviation)
- Group 2: 23mm +/- 22mm
- Group 3: 24mm +/- 26mm
There was no statistically significant difference between the groups.
This is a well done study and it is important considering how often the “pink lady” or “GI cocktail” is ordered in emergency departments. They did not include a placebo group, but that seems reasonable considering the numerous cited studies demonstrating benefit from antacids in the management of dyspepsia. (Goodson 1986; Graham 1983; Lanza 1986; Malmud 1978; Weberg 1989) Although all patients were blinded, it is unlikely blinding was successful considering the obvious clinical effects of lidocaine. Also, the volume provided in each group was different, so the assigned group would be pretty obvious.
One big issue with this study is that there really is no standard “GI cocktail”. It is possible that other combinations may be more effective than those tried here.
I had never heard of Donnatal, but I know a lot of people use Buscopan in Canada, which is a similar “antispasmodic” anticholinergic agent. I just reviewed the evidence on Buscopan for an upcoming episode of EM Cases, and it doesn’t seem to work very well. (Al-Waili 1998; Kumar 2004; Scheider 1993) However, there is an RCT in pediatric abdominal pain that just finished, and although the results haven’t been released yet, I have been told not to be too critical of Buscopan. (ClinicalTrials.gov NCT02582307)
However, Donnatal seems to be a particularly odd choice. It is a combination of belladonna alkaloids and phenobarbital, with a mechanism of action that slows GI motility. Considering the possible role of delayed gastric emptying in GERD and dyspepsia, I would think that this is the opposite of what we are trying to accomplish. That is a problem for this study, because viscous lidocaine was not tested on its own, but only in combination with Donnatal. It is possible that there is a benefit from viscous lidocaine, but that it was simply counteracted by Donnatal. (Although, to be fair, there is no hint of that in the results.)
They didn’t look for harms in this study. Lidocaine is unlikely to result is systemic symptoms at this dose, but anesthesia of the oropharynx could result in aspiration. Donnatal combines multiple drugs, all with many known side effects. Considering the lack of benefit seen, there is no reason to risk harm by adding these additional agents.
Using an antacid is reasonable in patients with dyspepsia, but there is no evidence to support the common practice of adding viscous lidocaine or other agents to that “GI cocktail”.
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