What medications are used to treat gas and bloating?

Medications for Gas and Bloating

For gas and bloating, start with antispasmodics for first-line symptom relief, then escalate to low-dose tricyclic antidepressants (10 mg amitriptyline titrated to 30-50 mg) if symptoms persist, as these are the most effective treatments supported by high-quality evidence. 1, 2

First-Line Pharmacological Options

Antispasmodics

• Antispasmodics are effective for global IBS symptoms and abdominal pain, though bloating relief is less consistently demonstrated. 1
• Common side effects include dry mouth, visual disturbance, and dizziness, which may limit tolerability. 1
• Careful dose titration can minimize adverse effects. 1
• Important caveat: Anticholinergic antispasmodics like hyoscyamine may worsen constipation and should be avoided if constipation coexists with bloating. 3

Simethicone

• Simethicone is an over-the-counter antifoaming agent commonly used for gas-related symptoms. 4, 5
• Evidence for simethicone's efficacy is mixed and contradictory—some studies show benefit when combined with other agents, while controlled trials show no effect on gas production or symptoms. 4, 5, 6
• A 2024 study demonstrated that chitin-glucan combined with simethicone improved bloating in 60% of IBS patients, though this was an open-label trial. 5
• The highest quality placebo-controlled study found no demonstrable effect of simethicone on symptoms or intestinal gas production. 6

Probiotics

• Probiotics may be tried for up to 12 weeks, but should be discontinued if there is no improvement in symptoms. 1
• Evidence quality is very low for their effectiveness in treating bloating. 1

Second-Line Treatments (When First-Line Fails)

Tricyclic Antidepressants (TCAs)

• TCAs are the most effective second-line treatment for bloating and abdominal pain, with strong evidence supporting their use. 1, 2
• Start with amitriptyline 10 mg once daily and titrate slowly (weekly or biweekly) to 30-50 mg once daily. 1, 2
• TCAs work by reducing visceral hypersensitivity through central neuromodulation, with 61% of patients reporting response for bloating symptoms. 2, 7
• Patients require counseling about the rationale (gut-brain axis modulation, not depression treatment) and side-effect profile. 1, 2
• Allow 6-8 weeks for response before declaring treatment failure. 2
• Continue treatment for 6-12 months after initial response to prevent relapse. 2

SSRIs/SNRIs

• Selective serotonin reuptake inhibitors may be effective as second-line gut-brain neuromodulators for global symptoms. 1
• SNRIs that activate both noradrenergic and serotonergic pathways (like duloxetine) are particularly useful for bloating with pain. 7
• Evidence quality is lower than for TCAs (low vs. moderate). 1

Treatments for Bloating with Constipation

Secretagogues

• Linaclotide, lubiprostone, and plecanatide have demonstrated superiority over placebo specifically for treating abdominal bloating in patients with constipation. 1, 7, 3
• Linaclotide 290 μg once daily is the most efficacious secretagogue for IBS with constipation, improving bloating in 4 trials with 3,061 patients. 1
• Diarrhea is the most common side effect with linaclotide and plecanatide. 1
• Lubiprostone 8 μg twice daily is less likely to cause diarrhea but frequently causes nausea. 1
• These agents work by increasing intestinal fluid secretion, softening stools and accelerating transit. 1

Polyethylene Glycol

• Polyethylene glycol is an effective and inexpensive option for chronic constipation that may indirectly improve bloating. 3

Specialized Treatments for Specific Causes

Rifaximin for SIBO/Dysbiosis

• Rifaximin is a non-absorbable antibiotic effective for bloating related to small intestinal bacterial overgrowth (SIBO) or suspected dysbiosis. 1, 7
• Dosing: 550 mg three times daily for 14 days. 8
• Rifaximin significantly reduces hydrogen production and overall severity of gas-related symptoms, including reducing flatus episodes and abdominal girth. 9
• The drug is FDA-approved for IBS with diarrhea but not available for this indication in many countries. 1
• Alternative antibiotics include amoxicillin, fluoroquinolones, and metronidazole, though these are less studied and more expensive. 1, 7
• Careful patient selection is required as antibiotics are not FDA-approved specifically for SIBO. 1

Dietary Interventions

• Identify and restrict dietary triggers through a short-term (2-week) elimination diet before escalating to medications. 1, 7
• Fructose intolerance affects 60% of patients with digestive disorders, compared to 51% for lactose intolerance. 1, 7
• Breath testing for hydrogen, methane, and CO2 can identify carbohydrate intolerances if dietary restriction fails. 1, 7
• Low-FODMAP diet should be considered as part of comprehensive management. 1, 7

Non-Pharmacological Adjuncts

Behavioral Therapies

• Diaphragmatic breathing techniques provide immediate relief by reducing vagal tone and correcting paradoxical diaphragm contraction. 1, 7
• Cognitive behavioral therapy and gut-directed hypnotherapy have robust evidence for improving bloating symptoms. 7
• FDA-approved prescription-based psychological therapies are now available via smartphone apps. 7

Treatment Algorithm

1. Start with dietary modification (2-week elimination of common triggers: lactose, fructose, FODMAPs). 1, 7

2. If symptoms persist, add antispasmodics (avoid anticholinergics if constipation present). 1, 3

3. For bloating with constipation, use secretagogues (linaclotide preferred for efficacy, lubiprostone if nausea tolerance is concern). 1, 3

4. For refractory symptoms, escalate to low-dose TCAs (amitriptyline 10 mg, titrate to 30-50 mg over 6-8 weeks). 1, 2

5. Consider rifaximin if SIBO risk factors present (prior antibiotics, diabetes, altered anatomy). 1, 7, 9

6. Add behavioral therapies (diaphragmatic breathing, CBT) at any stage. 7

Critical Pitfalls to Avoid

• Never start TCAs at standard antidepressant doses—begin low (10 mg) to minimize side effects and improve adherence. 2
• Avoid hyoscyamine and other anticholinergic antispasmodics in patients with constipation, as they will worsen symptoms. 3
• Do not discontinue TCAs prematurely—allow 6-8 weeks for response before declaring treatment failure. 2
• Set realistic expectations—complete symptom resolution is often not achievable; the goal is meaningful symptom reduction. 2
• Simethicone has the weakest evidence base despite widespread use—consider it only as an adjunct, not primary therapy. 6