Doxepin Dosage for Functional Dyspepsia
Direct Answer
Doxepin is not recommended for functional dyspepsia; amitriptyline is the preferred tricyclic antidepressant, starting at 10 mg once daily in the evening and titrating slowly to 30-50 mg daily. 1
Preferred Tricyclic Antidepressant Selection
The British Society of Gastroenterology specifically recommends amitriptyline as the tricyclic antidepressant of choice for functional dyspepsia, not doxepin. 1 This represents a strong recommendation with moderate-quality evidence. 1
Amitriptyline Dosing Protocol
- Starting dose: 10 mg once daily in the evening 1
- Titration: Increase slowly by 10 mg weekly or every 2 weeks to improve tolerability 1
- Target dose: 30-50 mg daily 1
- Trial duration: 6-8 weeks with at least 2 weeks at maximum tolerated dose 2
Alternative Tricyclic Options
If amitriptyline is not tolerated, nortriptyline (a secondary amine) can be considered as it has a theoretically more favorable side effect profile, though clinical evidence is stronger for amitriptyline. 1 For nortriptyline, start at 25 mg at bedtime and increase by 25 mg every 3-7 days as tolerated, up to 150 mg/day. 2
However, a 2018 randomized controlled trial found nortriptyline 10 mg daily was not superior to placebo in Asian patients with functional dyspepsia (response rate 53.6% vs 57.6%, P=0.75). 3
Treatment Algorithm Position
Tricyclic antidepressants should be initiated after failure of: 1
- H. pylori testing and eradication (if positive) 2, 1
- Proton pump inhibitor trial (4-8 weeks) 1, 4
- Prokinetic agents (acotiamide 100 mg three times daily or itopride) 5, 6
Tricyclic antidepressants rank second in network meta-analyses for functional dyspepsia treatment efficacy. 1
Evidence for Amitriptyline Efficacy
A 2015 multicenter randomized controlled trial demonstrated that amitriptyline 50 mg provided adequate relief in 53% of patients versus 40% with placebo (P=0.05). 7 The benefit was particularly pronounced in ulcer-like (painful) functional dyspepsia, where patients were 3-fold more likely to report adequate relief (odds ratio 3.1,95% CI: 1.1-9.0). 7
Patient Education and Side Effect Management
Critical counseling point: Explain that tricyclic antidepressants function as gut-brain neuromodulators, not antidepressants, to improve patient acceptance and adherence. 1
Common Side Effects
Slow titration significantly improves tolerability and reduces discontinuation rates. 1
Important Caveats
- Cardiac screening: Obtain baseline ECG in patients over 40 years before initiating therapy 2
- Cardiac caution: Use with caution in ischemic heart disease or ventricular conduction abnormalities, limiting doses to <100 mg/day when possible 2
- Delayed gastric emptying: Patients with documented delayed gastric emptying are less likely to respond to tricyclic antidepressants (odds ratio 0.4,95% CI: 0.2-0.8) 7
- Refractory cases: Consider referral to multidisciplinary pain centers or gastroenterology specialists for severe or treatment-resistant functional dyspepsia 1