What to do about chest pain and acid reflux after starting fluoxetine (selective serotonin reuptake inhibitor)?

Management of Chest Pain and Acid Reflux After Starting Fluoxetine

First, rule out cardiac causes immediately if chest pain is new or worsening—call 9-1-1 if chest pain is unimproved or worsening 5 minutes after onset, as cardiac evaluation must precede any assumption that symptoms are gastrointestinal in origin. 1

Immediate Assessment

• Cardiac evaluation is mandatory before attributing chest pain to acid reflux, as approximately 30% of non-cardiac chest pain cases are caused by gastroesophageal reflux, meaning 70% have other causes that must be excluded first 1
• If chest pain is unimproved or worsening 5 minutes after onset, activate emergency medical services immediately 1
• Once cardiac causes are definitively excluded through appropriate testing, proceed with gastrointestinal evaluation 1

Initial Management Strategy

Start a therapeutic trial of a proton pump inhibitor (PPI) at full dose twice daily for 4 weeks, as this is the recommended initial diagnostic and therapeutic approach for suspected GERD-related chest pain. 1

• The trial should be considered positive if there is at least 75% reduction in symptom frequency 1
• PPIs should be taken 30-60 minutes before meals (before breakfast and dinner) for optimal acid suppression 2
• This approach is more cost-effective than immediate reflux monitoring for chest pain suspected to be esophageal in origin 1

Fluoxetine-Specific Considerations

• Gastrointestinal adverse effects (including nausea and potentially reflux symptoms) are common with fluoxetine initiation but typically resolve over time 3, 4
• Common adverse events that occur in >5% of patients early in fluoxetine treatment decrease significantly in frequency over the first 6 months and resolve in the majority of patients 3
• No adverse events present initially become more frequent with continued treatment 3
• Consider continuing fluoxetine while managing reflux symptoms, as the gastrointestinal effects are likely to improve spontaneously within weeks to months 3

If Symptoms Persist Despite PPI Trial

Proceed with pH/impedance monitoring rather than pH monitoring alone, as this detects both acid and non-acid reflux episodes and provides superior diagnostic accuracy. 1, 2

• For patients with previous pathological findings (endoscopy or pH monitoring), perform testing ON twice-daily PPIs to assess adequacy of acid suppression 1, 2
• For patients without previous GERD confirmation, perform testing OFF PPIs to establish or exclude the diagnosis 1
• Both Symptom Association Probability (SAP) and Symptom Index (SI) should be assessed to determine if symptoms correlate with reflux episodes 1, 2

Diagnostic Workup Sequence

1. Endoscopy should be performed to evaluate for erosive esophagitis (Los Angeles classification), hiatal hernia, Barrett's esophagus, or eosinophilic esophagitis before proceeding to advanced imaging 1, 2

2. If endoscopy is negative and symptoms persist on twice-daily PPI, proceed with pH/impedance monitoring to phenotype the condition as:

   • Refractory non-erosive reflux disease
   • Hypersensitive esophagus
   • Functional heartburn 1, 2

3. CT scan should only be considered after failure of optimized PPI therapy and negative diagnostic workup 2

Common Pitfalls to Avoid

• Do not dismiss chest pain as "just reflux" without cardiac evaluation—this is the most critical error, as increased acid reflux is only one of several causes of chest pain of esophageal origin 1
• Do not discontinue fluoxetine prematurely for gastrointestinal symptoms, as these typically resolve with continued treatment 3
• Do not use pH monitoring alone in patients on PPIs—pH/impedance is required to detect non-acid reflux that may be causing persistent symptoms 1, 2
• Ensure PPI timing is optimized (30-60 minutes before meals) before concluding treatment failure 2

Medication Optimization

• If single-dose PPI is inadequate, increase to twice daily dosing before switching agents 1
• Consider adjunctive therapy based on symptom pattern: alginate antacids for breakthrough symptoms, H2 receptor antagonists for nocturnal symptoms, or baclofen for regurgitation-predominant symptoms 1
• Once adequate response is achieved, taper PPI to the lowest effective dose 1