Selective Serotonin Reuptake Inhibitors (SSRIs) and the Risk of Bleeding

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Selective serotonin reuptake inhibitors (SSRIs) are widely prescribed in the management of various conditions, including major depressive disorder, generalised anxiety disorder, obsessive-compulsive disorder, and post-traumatic stress disorder.

Evidence suggests that SSRIs are associated with an increased risk of bleeding, particularly at mucosal sites, with gastrointestinal (GI) haemorrhage being the primary clinical concern [1][2][3]. Observational studies and meta-analyses have demonstrated an increased risk of upper GI bleeding with SSRI use, particularly in patients receiving concomitant therapies such as nonsteroidal anti-inflammatory drugs (NSAIDs) or antiplatelet agents [2][3].

This article explores these risks in the context of prescribing practice and the use of clinical decision solutions, aiming to support safer decision-making and reducing medication errors.

Overview of SSRIs

SSRIs inhibit the serotonin transporter, thereby increasing serotonin availability within the synaptic cleft [1]. Some of the commonly prescribed SSRIs include:

• Fluoxetine
• Sertraline
• Citalopram
• Escitalopram
• Paroxetine
• Fluvoxamine

SSRIs may increase bleeding risk through their effects on platelet-mediated haemostasis. Platelets do not synthesise serotonin and depend on uptake of serotonin from plasma. By inhibiting the serotonin transporter, SSRIs reduce intraplatelet serotonin stores, which may impair platelet aggregation and prolong bleeding time, thereby increasing susceptibility to bleeding. Other mechanisms, including increased gastric acid secretion, may also contribute to the risk of upper GI bleeding [1].

Clinical manifestations of SSRI-associated bleeding

SSRI-associated bleeding may vary in severity and clinical presentation.

Examples of reported manifestations include:

• Upper GI bleeding
• Epistaxis
• Increased bruising
• Menorrhagia
• Rare but serious events such as intracranial haemorrhage

Upper GI bleeding remains the most frequently reported and clinically significant presentation across observational studies [2][3].

Risk amplification during combination therapy

The clinical impact of SSRI-associated bleeding is most pronounced when used in combination with other medicines that affect haemostasis.

Commonly implicated drug classes include [1][2][4]:

• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Antiplatelet agents (e.g. aspirin, clopidogrel)
• Oral anticoagulants (e.g. warfarin)

Clinical studies have shown that these combinations may have additive effects, thereby increasing bleeding risk. Concomitant use of SSRIs with NSAIDs or antiplatelet agents has been associated with a substantially higher risk of upper GI bleeding than SSRI therapy alone, as demonstrated in population-based cohort studies and meta-analyses [2][3].

Patient-related risk factors

The risk of bleeding associated with SSRIs may be influenced by patient-specific factors such as [1][4]:

• Advanced age
• History of GI ulceration or bleeding
• Concomitant use of medications affecting haemostasis (e.g. NSAIDs, antiplatelet agents, anticoagulants)
• Hepatic impairment

SSRI-associated bleeding risk is multifactorial and may be reduced through targeted prescribing strategies.

Practical risk-reduction approaches include:

• Assessment of baseline bleeding risk prior to SSRI initiation [1][2][5]
• Avoidance of unnecessary combination therapy with NSAIDs, antiplatelets, or anticoagulants [2][4]
• Use the lowest effective dose of SSRIs where clinically appropriate, especially in at-risk patients [6][7]
• Consideration of gastroprotective therapy (e.g. proton pump inhibitors) in patients at increased risk of gastrointestinal bleeding, particularly where combination therapy cannot be avoided [1][5]
• Monitor for signs and symptoms of GI bleeding with laboratory investigations if appropriate, especially in higher risk patients [1]

Integration with MIMS Clinical Decision Solutions

MIMS Clinical Decision Solutions, through MIMS Integrated, supports identification and management of SSRI-associated bleeding risks at the point of prescribing.

The Drug Interaction Alert module flags clinically significant interactions between SSRIs and medicines such as NSAIDs, antiplatelets, and anticoagulants, with evidence-based recommendations on management.

The Drug Health Alert module highlights bleeding as a potential adverse effect associated with SSRI therapy and provides guidance on monitoring and risk mitigation.

Conclusion

SSRI-associated bleeding risk is an important consideration in routine prescribing, particularly in patients receiving concomitant therapies or with additional risk factors.

Recognition of patient-level risk factors, careful review of concomitant therapies, and integration of clinical decision support tools are important in supporting consistent, evidence-based prescribing and minimising preventable bleeding complications.

References

1. Andrade C, Sandarsh S, Chethan KB et al. Serotonin reuptake inhibitor antidepressants and abnormal bleeding: a review for clinicians and a reconsideration of mechanisms. J Clin Psychiatry. 2010 Dec;71(12):1565-75. See more
2. Anglin R, Yuan Y, Moayyedi P et al. Risk of upper gastrointestinal bleeding with selective serotonin reuptake inhibitors with or without concurrent nonsteroidal anti-inflammatory use: a systematic review and meta-analysis. Am J Gastroenterol. 2014 Jun;109(6):811-9. See more
3. de Abajo FJ, Rodríguez LA, Montero D. Association between selective serotonin reuptake inhibitors and upper gastrointestinal bleeding: population based case-control study. BMJ. 1999 Oct 23;319(7217):1106-9. See more
4. Lanas Á, Carrera-Lasfuentes P, Arguedas Y et al. Risk of upper and lower gastrointestinal bleeding in patients taking nonsteroidal anti-inflammatory drugs, antiplatelet agents, or anticoagulants. Clin Gastroenterol Hepatol. 2015 May;13(5):906-12.e2. See more
5. Jiang HY, Chen HZ, Hu XJ et al. Use of selective serotonin reuptake inhibitors and risk of upper gastrointestinal bleeding: a systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2015 Jan;13(1):42–50. See more
6. Li YH, Hang LW, Muo CH et al. Dose of selective serotonin reuptake inhibitors and risk of upper gastrointestinal bleeding in older adults. J Psychopharmacol. 2024 Feb;38(2):137-144. See more
7. Öndemark M, Nordström L, Lindqvist PG. Dose-dependent increase in risk of bleeding and bleeding complications in relation to SSRI use at delivery. Eur J Obstet Gynecol Reprod Biol. 2024 May;296:265-269. See more