From the FDA Drug Label
Gastrointestinal: Nausea, vomiting, indigestion, taste disturbances, diarrhea, anorexia, and aphthous stomatitis have been reported. (See Anticholinergic Effects.) Anticholinergic Effects: Dry mouth, blurred vision, constipation, and urinary retention have been reported
The gastrointestinal risks associated with doxepin include:
- Nausea
- Vomiting
- Indigestion
- Taste disturbances
- Diarrhea
- Anorexia
- Aphthous stomatitis
- Constipation (as an anticholinergic effect) 1
From the Research
Doxepin can cause several gastrointestinal side effects, with the most common being constipation, dry mouth, nausea, and increased appetite that may lead to weight gain. These effects occur because doxepin, like other tricyclic antidepressants, blocks muscarinic acetylcholine receptors, which affects normal gut motility and secretions. Constipation may be particularly problematic in elderly patients or those with pre-existing bowel disorders. Dry mouth occurs in up to 25% of patients and can lead to difficulty swallowing or dental issues if persistent. Less commonly, doxepin may cause vomiting, abdominal pain, or taste disturbances. To manage these side effects, patients should maintain adequate hydration, increase dietary fiber, exercise regularly, and consider stool softeners for constipation. Sugar-free candies or artificial saliva products can help with dry mouth. If gastrointestinal side effects become severe or intolerable, dose reduction or medication change may be necessary after consulting with a healthcare provider. These effects typically improve with continued use as the body adjusts to the medication.
Some studies have investigated the risk of gastrointestinal bleeding associated with various medications, including NSAIDs and anticoagulants 2, 3, 4, 5. However, the most recent and relevant study regarding the risk of lower gastrointestinal bleeding in patients using NSAIDs and proton pump inhibitors found that the risk was significantly higher in NSAID+PPI users than in NSAID-only users 6. Although this study does not directly address doxepin, it highlights the importance of considering gastrointestinal risks when prescribing medications. In the context of doxepin, it is essential to monitor patients for gastrointestinal side effects and adjust treatment as needed to minimize the risk of morbidity and mortality. Patients should be educated on the potential gastrointestinal risks associated with doxepin and encouraged to report any severe or persistent symptoms to their healthcare provider. Regular follow-up appointments can help identify any potential issues early on, allowing for prompt intervention and minimizing the impact on the patient's quality of life. Overall, a careful balance between the benefits and risks of doxepin is necessary to ensure optimal patient outcomes.