Research has suggested that the reflux medication Famotidine can improve the odds of survival for Covid-19 patients, especially when it is combined with aspirin.

It also appears to hinder the severity of disease progression, making patients less likely to reach the point where they require intubation or a ventilator.

However, other studies suggest reflux drugs may double the risk of diagnosing positive for Covid-19.

Let’s take a look at the claims.

Famotidine has been linked to improved symptoms in patients with Covid-19, including cough, shortness of breath, fatigue, headaches and anosmia.

What is famotidine?

Famotidine belongs to a group of medicines known as histamine H2-receptor antagonists or H2-blockers.

These block the action of histamine in the stomach to decrease the production of stomach acid. Famotidine is known by the brand name Pepcid in the UK and the US.

Early China studies

In the early days of the pandemic, doctors who worked with coronavirus patients in Wuhan, China discovered that although one in five Covid-19 patients over the age of 80 died, many of those who survived had been taking famotidine.

Early US studies

Then, a small US study monitored the use of Famotidine in a group of 10 patients with Covid-19 and found that patients reported marked improvements of disease related symptoms after starting the medication.

Researchers concluded that high-dose oral Famotidine is ‘well tolerated and associated with improved patient-reported outcomes in non-hospitalised patients with Covid-19’.

All patients noticed a rapid improvement in their condition within 24 to 48 hours of starting famotidine. The study was published in the medical journal Gut in September 2020.

2021 global research

Data scientists have worked with an international team of researchers to analyse information from a database that holds the medical records of millions of Covid-19 patients living in 30 different countries.

It identified 22,000 people, in the largest sample size for a study on Famotidine.

The team’s analysis showed that the data supported findings from the previous smaller-scale studies. When delivered at high doses (the equivalent of about 10 Pepcid tablets), Famotidine appears to improve the odds of survival for Covid-19 patients, especially when it is combined with aspirin. It also seems to hinder the severity of disease progression, making patients less likely to reach the point where they require intubation or a ventilator.

Why would this medication work?

Some researchers say that histamine release may contribute to the inflammation associated with Covid-19 infection. Viruses activate mast cells – widely distributed in the gastrointestinal tract – that release early inflammatory chemical compounds, such as histamine and protease.

Covid-19 can trigger in your body something called a cytokine storm, which is a potentially fatal amplification of an immune response. When you become sick, your immune system releases inflammatory proteins called cytokines that tell your immune cells how to fight the infection.

Researchers theorise that famotidine suppresses that reaction.

So, does this mean Pepcid can stop the coronavirus?

It is important to remember that these studies are in the early stages. Researchers warn that while its findings suggest that famotidine may affect the course of Covid-19, they must be considered in the context of several limitations.

Placebo effect, enrolment bias and recall bias for symptoms may affect findings. There also remains the possibility that changes may reflect treatment independent convalescence, as the natural course of Covid-19 in patients who do not require hospital admission is not well known.

One researcher, Dr Tracey, told the US news publication that ‘patients in the study are in the hospital taking mega-doses intravenously – about nine times what someone would normally take for heartburn’ and warned that people ‘should not go to the drugstore and take a bunch of heartburn medicine.’

I thought H2-receptors were dangerous anyway?

Last year, drug companies recalled the H2 blocker ranitidine after the cancer-causing chemical N-nitrosodimethylamine (NDMA) was spotted in versions of the medication.

However, none of the other H2 blockers – including famotidine – have been found unsafe.

PPIs causing positive Covid-19 tests

According to a study published in the American Journal of Gastroenterology, usage of proton pump inhibitors (PPIs), in particular twice-daily dosing, have been correlated with increased odds for reporting a positive Covid-19 test.

The US study found that use of PPIs does not lead to an increase of Covid-19 symptoms but proposed that PPI-induced hypochlorhydria can impair the body’s proximal defence against ingested bacteria and viruses.

Another study in China, found that laryngopharyngeal reflux disease (LPR) is ‘commonly prevalent in hospitalised patients with Covid‐19 and independently associated with risk of severe or critical infection’ from the virus.

However, in response to the study other experts said ‘many points have to be addressed regarding the methodology and the conclusion of the study. In an article, it was suggested that any study into reflux and Covid-19 should involve a non-invasive objective approach, such as pepsin saliva detection.


Several studies show relationships between Famotidine and positive outcomes in Covid-19 and several do not.

In a 2021 review, experts warn that the conflicting data and conclusions related to Famotidine must be resolved before it can be useful for drug discovery and repurposing.

It warned that ‘the contradictions and potential confusion have ramifications for clinicians faced with choosing therapeutically optimal courses of intervention’.

Professor Peter Dettmar also warns: “Studies so far have been very small and largely observational so it would be far too early to make any conclusions from them. Larger, controlled studies that involve other related medication would be needed to confirm how and if they can change the course of Covid-19. The use of Peptest® for the determination of salivary pepsin in Covid-19 patients as a biomarker for reflux disease could be an important tool in such studies.”

This blog – updated in September 2021 – is for informational purposes only and does not include recommendations nor endorsements.

An early and objective diagnosis of reflux, such as Peptest provides, opens the door to lifestyle changes, and future treatment. Peptest can also be used after reflux treatments to assess the success or failure of any treatment. Find out more about Peptest and order your Peptest home testing kit now.


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