Symptomatic & Acute Treatment Medications
Medications that treat specific gut symptoms as they occur. Choice depends on exact symptom cluster (acid, cramping, motility, nausea). Many are available over the counter — but "OTC doesn't mean indefinite use."
🔥 Proton Pump Inhibitors (PPIs) — First-line for GERD, erosive esophagitis
Mechanism: Irreversibly inhibit H+/K+ ATPase in parietal cells, reducing gastric acid production by 90%+. 4.5 taken 30-60 min before breakfast.
Medications: Omeprazole 20-40mg · Pantoprazole 40mg · Rabeprazole 20mg · Esomeprazole 20-40mg · Lansoprazole 30mg.
When to use: GERD symptoms, erosive esophagitis, PPI-responsive dyspepsia, Barrett's esophagus, H. pylori eradication (with antibiotics), peptic ulcer disease, NSAID gastroprotection.
Side effects (long-term use): Vitamin B12 deficiency, magnesium deficiency, osteoporosis/fracture risk, C. difficile infection, community-acquired pneumonia, interstitial nephritis. Rebound acid hypersecretion on discontinuation.
Deprescribing: Should NOT be indefinite without clear ongoing indication. Step down to lowest effective dose or on-demand use. Taper over 4-8 weeks to avoid rebound.
💊 H2 Receptor Antagonists — Alternative acid suppression
Mechanism: Block histamine H2 receptors on parietal cells, reducing acid production by 60-70%. Faster onset but weaker than PPIs.
Medications: Famotidine 20-40mg · Ranitidine (withdrawn due to NDMA contamination) · Nizatidine · Cimetidine (many drug interactions).
When to use: Mild/intermittent GERD, PRN basis, on-demand before trigger foods, overnight breakthrough acid, PPI tapering bridge. Pregnancy-safer than PPIs.
Side effects: Generally very well tolerated. Headache, dizziness. Tolerance develops with daily use. Cimetidine inhibits CYP enzymes — many drug interactions.
🫁 Antispasmodics — Cramping and IBS pain
Mechanism: Relax smooth muscle of GI tract via anticholinergic action or direct smooth muscle relaxation.
Medications: Hyoscine (Buscopan) 10mg before meals · Mebeverine 135mg TID · Peppermint oil enteric-coated · Dicyclomine · Alverine citrate.
When to use: IBS cramping pain, functional abdominal pain, before meals that typically trigger symptoms.
Side effects: Dry mouth, blurred vision, constipation, urinary retention (anticholinergic). Peppermint oil can worsen GERD. Avoid in glaucoma, prostate enlargement, intestinal obstruction.
🚽 Prokinetics — Motility stimulation
Mechanism: Enhance GI motility through various mechanisms (5-HT4 agonism, dopamine antagonism).
Medications: Prucalopride 1-2mg daily (selective 5-HT4) · Metoclopramide 10mg TID (short-term only due to tardive dyskinesia risk) · Domperidone 10mg TID (QT prolongation concerns) · Itopride.
When to use: Gastroparesis, IBS-C, chronic idiopathic constipation unresponsive to laxatives, functional dyspepsia with delayed emptying.
Side effects: Headache, diarrhea, nausea (prucalopride). Extrapyramidal symptoms, hyperprolactinemia, tardive dyskinesia (metoclopramide — max 12 weeks). QT prolongation (domperidone).
💩 Laxatives & Anti-diarrheals
Osmotic laxatives (first-line for constipation): Polyethylene glycol (PEG, Macrogol) 17g daily · Lactulose 15-30mL · Milk of magnesia. Safe for long-term use.
Stimulant laxatives (short-term only): Senna 15-30mg · Bisacodyl 5-10mg. Avoid chronic use (though less harm than previously believed).
Fiber supplements: Psyllium husk 10-20g daily (soluble, works for both constipation and diarrhea) · Methylcellulose · Wheat dextrin.
Anti-diarrheals: Loperamide 2-4mg (max 16mg/day) · Diphenoxylate-atropine · Bile acid sequestrants (cholestyramine) for bile acid diarrhea.
Anti-emetics: Ondansetron 4-8mg (5-HT3 antagonist, can cause constipation) · Metoclopramide · Prochlorperazine · Promethazine.