I’m sure you’ve all heard of the Pepcid AC Asian flush challenge. If not, you’ve probably heard about a friend who takes Pepcid AC, Zantac or some other antacids to stop their Asian Flush.
If you’re still not familiar with this method you can watch a video below of a YouTube user taking the Pepcid AC Asian flush challenge himself. It’s a commonly used trick that has been doing the rounds since the 80’s when some scientists linked the function of h2 receptor antagonists (like Pepcid and Zantac) to a decreased flushing response in subjects who suffered from ALDH2 deficiency (i.e. alcohol flush reaction).
Does it work? Let’s hear what Youtube user phampants has to say about it:
As you can see it worked well. Granted, we don’t have any idea how badly the YouTube user normally suffers from alcohol flushing, but from what the video showed the Pepcid seemed to have an effect.
Is there solid evidence that antacids like Pepcid AC can stop alcohol flush reaction?
A lot of the information about the efficacy of Pepcid AC in stopping alcohol flushing is anecdotal. In fact, it is widely spoken about on internet forums as the go-to solution for alcohol flush reaction. But is there any science out there that delves into how Pepcid stops alcohol flushing?
In a 1988 study, researchers looked at the effectiveness of various antihistamines in stopping alcohol-induced flushing in Orientals:
Before the administration of alcohol, one-half of the subjects were given 50 mg of diphenhydramine (H1 receptor antagonist) and 300 mg of cimetidine (H2 receptor antagonist). The second half received placebo tablets. The clearest difference between the antihistamine group and placebo group was in the skin flushing reaction. The antihistamine group showed a significant reduction in the skin flush. The antihistamine also neutralized the systolic hypotension induced by the administration of alcohol.
Whilst Pepcid AC was not specifically tested in this study, the results garnered from the testing of cimetidine has some relevance because they are both a part of the same group of antihistamines called H2 receptor antagonists.
The study above showed that even when taken alone, h2 receptor antagonists like Pepcid can reduce flushing from alcohol. But the researchers fell short of explaining exactly how they are able to do this.
How do Pepcid AC and other antacids stop alcohol flush reaction?
The science is not clear on the precise mechanism with which Pepcid AC affects alcohol flushing. That said, there are some clues from which we can draw educated guesses.
In our article titled “What is Alcohol Flush Reaction?“, we explain that the reason you flush red after drinking alcohol is that your body is not breaking down a toxic alcohol metabolite called acetaldehyde.
Acetaldehyde makes your face turn red via what is known as a histamine release. Your body has histamine receptors all over the place that detect histamine and cause a reaction. One particular type, called H2 receptors, are found in vascular smooth muscle where their function is to mediate vasodilation (i.e. the widening of blood vessels). When triggered, these H2 receptors can cause blood vessels in the face and neck to widen and make the skin around those areas appear redder.
The purpose of antihistamines is to block histamine receptors and prevent them from reacting to histamines released in the body. In particular, the function of antihistamines of the H2 receptor antagonist variety, like Pepcid and Zantac, blocks the reaction of the H2 histamine receptors that cause blood vessel dilation in the face and neck region.
By doing this, Pepcid and Zantac may prevent alcohol flushing by simply masking the flushing. This is problematic because acetaldehyde can harm your body in ways far scarier than flushed cheeks.
Serious health implication of taking Pepcid AC, Zantac and other antacids to prevent Asian Flush
In our article titled Alcohol Flushing and Cancer, we explain how acetaldehyde has been flagged as a cancer-causing carcinogen by a number of the most highly regarded governmental health bodies in the world.
What this means is that if you suffer from alcohol flush reaction, your body is being subject to more acetaldehyde than the normal person and this causes your risk of a lot of nasty cancers to increase dramatically. Therefore, simply taking Pepcid to mask the symptoms of alcohol flushing may not be such a good idea.
When interviewed for an article about antacids and Asian flush, Sean Nordt, toxicologist and associate professor of clinical emergency medicine at the Keck School of Medicine of USC, stated:
“They’re turning red for a reason: Acetaldehyde is in their system … This is their body telling them to stop drinking immediately. I know it’s frustrating for people because it may be challenging being surrounded by people who drink often … If people want to take H2 blockers (like Pepcid and Zantac), the best thing to do is to discuss their decision with their physician and figure out a game plan rather than treating themselves.”
The director of USC’s Alcohol and Brain Research Laboratory echoes these cautionary statements and reiterates that alcohol flush reaction is your body telling you to slow down and start hydrating:
“Using histamine-2 blockers (like Pepcid and Zantac) to reduce the ‘Asian flush’ can escalate alcohol intake and increase the risk of stomach cancers, esophageal cancer and a type of skin cancer called squamous cell carcinoma … The use of H2 blockers may allow someone suffering from Asian glow to drink higher levels of alcohol, but this person shouldn’t do that. It’s just not smart.”
It seems clear that, from strong anecdotal evidence and a small number of clinical trials, the Pepcid AC Asian flush trick does reduce facial flushing after consuming alcohol. However, to the extent that it only does so via antihistamine activity, this “off label” use of antacids fails to address the cause of alcohol flush reaction and exposes the user to various long-term risks associated with acetaldehyde toxicity.
A preferred alternative to the Pepcid AC Asian flush method is one that can reduce Asian flush symptoms and also reduce blood acetaldehyde to protect the body against long-term health implications of persistent acetaldehyde exposure.