| Drug (Brand) | Class | Dose | Onset | Key Notes |
|---|---|---|---|---|
| Docusate (Colace) NOT RECOMMENDED | Stool softener | , | , | No better than placebo. Omitted from all AGA-ACG 2023 recommendations. Removed from hospital formularies (UAB 2024). No FDA-approved indication. Do not prescribe. |
| PEG 3350 (MiraLAX) 1ST LINE | Osmotic laxative | 17g in 8 oz water PO daily–BID | 24–48h | First-line per AGA-ACG 2023 (strong recommendation, moderate evidence). Non-absorbed. Less bloating than lactulose. Safe in CKD. Can increase to TID if refractory. |
| Senna (Senokot) 2ND LINE | Stimulant laxative | 8.6–17.2 mg PO BID (1–2 tabs) | 6–12h | Add to PEG. Stimulates colonic motility via myenteric plexus. In OIC, start PEG + senna together from day 1. Conditional recommendation per AGA-ACG 2023. |
| Bisacodyl (Dulcolax) ESCALATION | Stimulant laxative | 10 mg PO daily or 10 mg PR | PO: 6–12h PR: 15–60 min | Add when PEG + senna insufficient. PR suppository much faster. Strong recommendation per AGA-ACG 2023. Avoid in acute abdomen or bowel obstruction. |
| Lactulose (Kristalose) ALTERNATIVE | Osmotic laxative | 15–30 mL PO q6–8h | 24–48h | Also used for hepatic encephalopathy (different dose: 30–45 mL q1–2h until BM). More bloating/gas than MiraLAX. |
| Methylnaltrexone (Relistor) OIC-SPECIFIC | Peripheral μ-opioid antagonist | 8 mg SC (< 62 kg) or 12 mg SC (≥ 62 kg) q48h | 30 min–4h | Targets opioid-induced constipation (OIC) specifically. Does NOT cross BBB -no reversal of analgesia or withdrawal. Expensive. Use after standard regimen fails. |
| Naloxegol (Movantik) OIC-SPECIFIC | Peripheral μ-opioid antagonist (PO) | 25 mg PO daily (12.5 mg if CrCl < 60 or moderate CYP3A4 inhibitor) | 6–12h | Oral alternative to methylnaltrexone. Avoid with strong CYP3A4 inhibitors. Renal dose needed. |
| Magnesium citrate ADJUNCT | Osmotic / saline laxative | 150–300 mL PO × 1 | 30 min–3h | Fast-acting. Avoid in renal failure (hypermagnesemia). Single-use, not for maintenance. |
| Soap suds enema (SSE) RESCUE | Rectal enema | 1500 mL warm water + castile soap PR | 5–30 min | First-line rectal intervention. Safe in CKD. Stimulates peristalsis via distension + mild irritation. Preferred over Fleet in renal patients. |
| Tap water enema RESCUE | Rectal enema | 500–1000 mL warm tap water PR | 5–30 min | Alternative to SSE. Safe in CKD. Less effective than SSE but gentler. Can repeat. |
| Fleet enema (sodium phosphate) ACUTE ONLY | Rectal enema | 1 bottle (133 mL) PR × 1 | 2–15 min | ⚠️ Avoid in CKD, can cause fatal hyperphosphatemia. Avoid in elderly, dehydrated, or bowel obstruction. Use SSE or tap water enema instead. |
| Scenario | Approach |
|---|---|
| Opioid-induced (most ICU patients) | PEG 3350 + senna from day 1 → escalate per protocol. Methylnaltrexone if refractory. Consider opioid rotation or reduction. |
| Post-operative ileus | Ambulation is the best treatment. Gum chewing stimulates gut motility. Alvimopan (Entereg) 12 mg PO BID × 7 days for post-surgical ileus (hospital use only). Avoid NG tube for uncomplicated ileus. |
| Hepatic encephalopathy | Lactulose 30–45 mL q1–2h titrated to 3–4 BMs/day. Goal is ammonia clearance, not just bowel movement. Rifaximin 550 mg PO BID for maintenance. See HE topic. |
| Hyperkalemia (kayexalate alternative) | Patiromer (Veltassa) or sodium zirconium (Lokelma) preferred over sodium polystyrene sulfonate (Kayexalate) -Kayexalate has risk of bowel necrosis and questionable efficacy. |
| CKD / dialysis patients | Avoid Fleet enemas (hyperphosphatemia), magnesium-containing laxatives (hypermagnesemia), and mineral oil (aspiration risk). Use PEG 3350 + senna (MiraLAX), lactulose, or bisacodyl. Lactulose is safe in CKD and can be used as PEG alternative. |
| C. difficile concern | If new diarrhea after bowel regimen → check C. diff toxin. Hold laxatives. If C. diff positive: fidaxomicin 200 mg PO BID × 10d (preferred) or vancomycin 125 mg PO QID × 10d. Avoid loperamide. |
| Drug (Brand) | Class | Dose | Onset | Key Notes |
|---|---|---|---|---|
| Loperamide (Imodium) 1ST LINE | Peripheral μ-opioid agonist | 4 mg × 1, then 2 mg after each loose stool | 1–3h | Max 16 mg/day. ⚠️ CONTRAINDICATED in C. diff, bloody diarrhea, toxic megacolon, ileus. Does not cross BBB at standard doses. Safe in CKD. OTC. |
| Bismuth subsalicylate (Pepto-Bismol) ADJUNCT | Antisecretory / antimicrobial | 524 mg (2 tabs) PO q30min–1h PRN | 30–60 min | Max 8 doses/day. Avoid with aspirin allergy or anticoagulants (salicylate content). Turns stool/tongue black (harmless). Helpful for traveler's diarrhea. |
| Diphenoxylate-atropine (Lomotil) 2ND LINE | Opioid agonist + anticholinergic | 5 mg/0.05 mg: 2 tabs QID, then taper | 45–60 min | Schedule V controlled. Atropine added to discourage abuse. Same contraindications as loperamide. May cause anticholinergic effects at high doses. |
| Cholestyramine (Questran) BILE ACID | Bile acid sequestrant | 4 g PO BID–TID (mix in water) | 24–48h | First-line for bile acid diarrhea (post-cholecystectomy, ileal resection, Crohn's). Binds bile acids in gut. Must take 1h before or 4h after other meds (impairs absorption). |
| Octreotide (Sandostatin) REFRACTORY | Somatostatin analog | 50–100 mcg SC q8h (can ↑ to 500 mcg) | 30 min | For secretory / high-output diarrhea: carcinoid, VIPoma, short gut syndrome, chemo-induced, refractory to other agents. Also used for GI fistula output reduction. Expensive. |
| Psyllium (Metamucil) BULK FORMER | Soluble fiber | 1 rounded tsp (3.4 g) in 8 oz water PO TID | 12–72h | Absorbs water → bulks stool. Helpful for tube feed diarrhea and mild functional diarrhea. Must take with adequate water (risk of obstruction if dehydrated). Also used for IBS-D. |
| Probiotics (Saccharomyces boulardii) ADJUNCT | Live yeast probiotic | 250–500 mg PO BID | Days | Best evidence for antibiotic-associated diarrhea prevention. Goldenberg, Cochrane 2017. Avoid in immunocompromised (risk of fungemia). Not effective for acute C. diff treatment. |
| Kaolin-pectin (Kaopectate) ADJUNCT | Adsorbent | 60–120 mL PO after each loose stool | Variable | Mild effect. Adsorbs toxins and bacteria. Safe but less effective than loperamide. Can impair absorption of other medications. |
| Cause | Intervention |
|---|---|
| Rate too high | Reduce rate by 25%. Advance slowly (10–20 mL/h q4–6h). Continuous feeds cause less diarrhea than bolus feeds. |
| Hyperosmolar formula | Switch to isotonic, peptide-based formula (e.g., Peptamen, Vital AF). Elemental formulas for severe malabsorption. |
| Sorbitol in medications | Switch liquid meds to tablet/crush form. Common culprits: liquid acetaminophen, KCl elixir, liquid theophylline. Each 5 mL of sorbitol-containing elixir adds osmotic load. |
| Fiber deficiency | Add soluble fiber supplement (banana flakes 2 tbsp q8h via tube, or switch to fiber-enriched formula like Jevity 1.2 or Promote with Fiber). |
| Contamination | Replace tubing q24h. Use closed-system ready-to-hang bags. Hang time ≤ 8h for open systems. Check for improper storage. |
| C. diff | Always rule out even in tube-fed patients. Do NOT stop feeds for C. diff, trophic feeding maintains gut mucosal integrity. |