Can SSRIs Cause Gastritis? Understanding the Link Between Antidepressants and Gastrointestinal Issues

October 11, 2025 •

4 min read

According to a review published in BMC Psychiatry, a significant number of patients prescribed selective serotonin reuptake inhibitors (SSRIs) experience digestive side effects, including dyspepsia, stomach discomfort, and nausea, which can mimic symptoms of gastritis. While SSRIs may not cause true inflammatory gastritis in the same way as an infection, they can increase the risk of upper gastrointestinal issues and bleeding, especially when combined with other medications.

Quick Summary

SSRIs can cause a range of gastrointestinal symptoms resembling gastritis, such as upset stomach, nausea, and abdominal pain, by affecting serotonin levels in the gut. They also carry an increased risk of GI bleeding, intensified by NSAID use. Managing these side effects often involves timing medication or dietary adjustments, but a healthcare provider should always be consulted for persistent symptoms.

Key Points

SSRI GI Side Effects Resemble Gastritis: SSRIs can cause symptoms like nausea, stomach pain, and dyspepsia by affecting serotonin in the gut, which can feel like gastritis.
Risk of GI Bleeding is Increased: By inhibiting serotonin reuptake in platelets, SSRIs can reduce the blood's ability to clot, significantly increasing the risk of upper gastrointestinal bleeding.
NSAID Interaction Magnifies Risk: Combining SSRIs with NSAIDs dramatically increases the risk of GI bleeding because they cause mucosal damage and impair clotting simultaneously.
GI Side Effects Vary by SSRI: The frequency and type of gastrointestinal side effects differ among specific SSRIs; for instance, Sertraline is associated with higher rates of nausea and diarrhea compared to Escitalopram.
Symptoms Often Improve Over Time: For many, GI side effects are most prominent during the initial weeks of treatment and tend to subside as the body adapts to the medication.
Consult a Doctor for Management: Any persistent or severe GI symptoms should be reported to a healthcare provider, who may suggest dose adjustments, medication changes, or other management strategies.

The Connection Between SSRIs and Gastrointestinal Distress

Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants commonly prescribed for mood disorders like depression and anxiety. While they are generally better tolerated than older antidepressants, a significant portion of patients report gastrointestinal (GI) side effects. Many of these side effects, such as abdominal pain, nausea, and dyspepsia (indigestion), closely resemble the symptoms of gastritis, which is inflammation of the stomach lining.

Unlike an infection from H. pylori or prolonged NSAID use, which are direct causes of gastritis, the mechanism by which SSRIs affect the stomach is related to their primary function: altering serotonin levels. However, because serotonin is also a crucial neurotransmitter in the gut, this can lead to digestive disturbances. It is important to note that the GI tract contains more serotonin than the brain, making it particularly sensitive to changes in serotonin signaling.

How SSRIs Affect the Gastrointestinal System

The digestive side effects of SSRIs stem from several mechanisms related to increased serotonin activity outside the central nervous system:

Increased Gastric Acid Secretion: Elevated systemic serotonin can increase the production of gastric acid. This can lead to irritation and erosion of the stomach lining over time, which increases the risk of ulceration and bleeding.
Altered Gastric Motility: Serotonin plays a major role in regulating the movement of the gut. By increasing serotonin signaling in the enteric nervous system, SSRIs can disrupt normal peristalsis, leading to common side effects like nausea, diarrhea, or constipation.
Impaired Platelet Function: The serotonin transporter (SERT) is also found in blood platelets, where it is involved in blood clotting. SSRIs inhibit SERT, which reduces the amount of serotonin in platelets and impairs their ability to aggregate and form clots. This mechanism is a key contributor to the increased risk of GI bleeding associated with SSRI use.

Symptoms and Risk Factors

The GI symptoms experienced by patients on SSRIs can vary in intensity and are often most pronounced during the first few weeks of treatment as the body adjusts to the medication. Common symptoms include:

Nausea and vomiting
Abdominal pain or discomfort
Dyspepsia and heartburn
Diarrhea or constipation
Decreased appetite

Key Risk Factors for Gastric Issues with SSRIs:

Concomitant Use with NSAIDs: The risk of upper GI bleeding is significantly higher when SSRIs are taken with nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen. NSAIDs damage the gastric mucosa directly, while SSRIs impair clotting, creating a dangerous combination.
Other Medications: Combining SSRIs with other drugs that increase bleeding risk, such as blood thinners (e.g., warfarin), also heightens the risk of complications.
Dose Dependency: Some evidence suggests that the severity of side effects can be dose-dependent, meaning higher doses may increase the risk of GI issues.

Managing GI Side Effects from SSRIs

Addressing gastrointestinal discomfort from SSRIs should be done in consultation with a healthcare provider. Strategies may include:

Taking medication with food: This can help minimize stomach upset and irritation.
Adjusting the dose: A doctor might recommend starting with a lower dose and slowly titrating upward to allow the body to adjust.
Switching SSRIs: As a meta-analysis showed variations in GI side effects between different SSRIs, a different medication may be better tolerated.
Symptom Management: Over-the-counter antacids or dietary changes (e.g., avoiding acidic or spicy foods) can help relieve symptoms of heartburn or dyspepsia.
Addressing the underlying issue: For severe symptoms or bleeding, a full medical workup is necessary to rule out ulcers or other complications.

SSRI Comparison for Gastrointestinal Side Effects


SSRI Drug	Common GI Side Effects	Comparative GI Tolerability	Notes
Sertraline	Nausea, diarrhea, stomach pain	Lower gastrointestinal tolerability	Associated with higher frequency of nausea and diarrhea.
Escitalopram	Nausea, diarrhea, indigestion	Higher gastrointestinal tolerability	Often considered to have fewer GI side effects than Sertraline or Paroxetine.
Paroxetine	Nausea, constipation	Lower gastrointestinal tolerability	Can delay upper gastrointestinal transit, potentially causing constipation.
Fluoxetine	Nausea, diarrhea	Good gastrointestinal tolerability	A network meta-analysis found it to have a lower probability of digestive side effects compared to other SSRIs.

Conclusion

While the term 'gastritis' implies a direct inflammatory process, it is more accurate to say that SSRIs can cause significant gastrointestinal distress and increase the risk of more serious issues like GI bleeding through their effects on serotonin and platelet function. For most people, the GI side effects are mild and transient, particularly during the initial phase of treatment. However, for some, they can be persistent and problematic. It is crucial for patients to report any stomach pain, nausea, or signs of bleeding (like black, tarry stools) to their doctor immediately. Healthcare providers should carefully consider individual risk factors, especially concurrent medication use, and discuss potential GI issues with patients before starting SSRI therapy. Further reading on the link between SSRIs and GI effects can be found on the National Institutes of Health website.

Frequently Asked Questions

SSRI-induced stomach problems are caused by the medication's effect on serotonin, a neurotransmitter that is also heavily concentrated in the gut. This can lead to increased gastric acid, altered gut motility (movement), and impaired platelet function, all contributing to stomach upset and discomfort.

Yes, gastrointestinal side effects from SSRIs are very common, especially at the beginning of treatment. Symptoms like nausea, diarrhea, and abdominal pain are frequently reported as the body adjusts to the changes in serotonin levels.

To potentially minimize stomach issues, a doctor might advise starting with a lower dose and increasing it gradually. Taking the medication with food can also help reduce stomach upset.

Yes, different SSRIs have varying degrees of gastrointestinal side effects. For example, some studies suggest that fluoxetine and escitalopram may have better GI tolerability compared to sertraline.

If you experience severe stomach pain, especially if accompanied by signs of bleeding like black, tarry stools, or vomiting blood, seek immediate medical attention. This could indicate a more serious issue, such as an ulcer.

For mild symptoms like heartburn, an antacid may provide relief. However, always consult your doctor before taking any over-the-counter medications, as some may have interactions or mask more serious problems.

For many individuals, the gastrointestinal side effects are acute and tend to diminish over the first few weeks as the body undergoes physiological adaptation to the medication. If symptoms persist, a doctor should be consulted.

No, the risk of GI bleeding is significantly higher when SSRIs are used in combination with other drugs that affect clotting or damage the stomach lining, most notably nonsteroidal anti-inflammatory drugs (NSAIDs).