Antibiotics for Biliary Infections
| Scenario | Preferred Antibiotic(s) | Coverage | Notes |
|---|
| Acute cholecystitis (mild-moderate) | Cefazolin (IV) or cephalexin (PO) | Gram-negative enteric organisms (E. coli, Klebsiella) | Start pre-op; short perioperative course; CEFAZOLIN is 1st line for surgical prophylaxis for cholecystectomy |
| Acute cholecystitis (severe/high-risk) | Piperacillin-tazobactam (Zosyn) or ceftriaxone + metronidazole | Broad gram-negative + anaerobic coverage | Treat until cholecystectomy or resolution; add metronidazole for anaerobic coverage in complicated cases |
| Ascending cholangitis (biliary emergency) | Piperacillin-tazobactam OR ceftriaxone + metronidazole; carbapenems for severe/ICU | Gram-negative aerobic (E. coli, Klebsiella, Enterococcus) + anaerobes | Blood cultures BEFORE antibiotics; urgent ERCP for biliary decompression is definitive; IV vancomycin if Enterococcus suspected |
| SBP prophylaxis (related to biliary disease) | Norfloxacin 400mg daily or ciprofloxacin 500mg daily | Gram-negative enteric organisms | Long-term prophylaxis in cirrhotic patients with low-protein ascites or prior SBP episode |
🎯 Boards PearlAntibiotic selection in biliary disease follows biliary flora: E. coli (most common), Klebsiella, Enterococcus, and anaerobes in complicated/elderly/post-procedural cases. Empiric coverage should always cover gram-negatives. Add anaerobic coverage (metronidazole) for complicated cholangitis, gangrenous cholecystitis, or elderly patients. Duration: usually 4–7 days (or until afebrile × 24–48h for uncomplicated cholecystitis).
Gallstone Dissolution Therapy
| Drug | Indication | Mechanism | Criteria & Response |
|---|
| Ursodeoxycholic acid (UDCA / ursodiol) | Dissolution of small cholesterol gallstones in patients who are poor surgical candidates; prevention of gallstone formation during rapid weight loss | Hydrophilic bile acid → reduces cholesterol saturation of bile → gradual dissolution of cholesterol stones | Requires: cholesterol stones (not pigment), small (<5mm best; <20mm maximum), radiolucent on plain film, patent cystic duct, functioning GB. Duration: 6–24 months. Success: 40–60% dissolution for small stones; recurrence 50% at 5 years after stopping |
🏥 When to Choose Medical vs. SurgicalElective laparoscopic cholecystectomy is definitive treatment for symptomatic gallstones and is preferred when patient is a surgical candidate. Ursodiol is reserved for: patients refusing surgery, very high surgical risk, or prevention of stone formation (e.g., on rapid weight loss program, total parenteral nutrition). Ursodiol does NOT dissolve pigment stones, calcium-containing stones, or stones >20mm.
Cholestasis & Pruritus Management
| Drug | Mechanism | Use | Key Points |
|---|
| Cholestyramine (Questran) | Bile acid sequestrant → binds bile acids in gut → reduces enterohepatic recirculation → decreases bile acid-mediated itch | Pruritus from cholestasis (PBC, cholestatic jaundice), hyperlipidemia | Give at least 1 hour before (or 4–6 hours after) other medications — impairs absorption of fat-soluble vitamins (A, D, E, K), digoxin, warfarin, thyroid hormones, statins. Side effects: constipation, bloating |
| Colesevelam (Welchol) | Newer bile acid sequestrant; fewer drug interactions | Pruritus, hyperlipidemia; also reduces glucose (adjunct for T2DM) | Fewer drug interactions than cholestyramine; tablet form (better tolerability) |
| Rifampin | PXR nuclear receptor agonist → induces hydroxylation and sulfation of bile acids; also induces CYP enzymes → alters bile acid metabolism | Refractory cholestatic pruritus (PBC, PSC) | 150–300mg BID; check LFTs — can cause hepatotoxicity; induces CYP3A4 → many drug interactions (reduces warfarin, OCP, statin effectiveness) |
| Naltrexone / Naloxone | Opioid receptor antagonist → blocks endogenous opioid-mediated itch signaling in cholestasis | Refractory cholestatic pruritus; second or third-line | Start low dose (25mg/day naltrexone) to avoid opioid withdrawal reaction in opioid-naive patients |
| Sertraline (SSRI) | Unknown mechanism in cholestatic pruritus; may modulate central itch perception | Refractory cholestatic pruritus; adjunct therapy | 75–100mg/day; well-tolerated; can be combined with other agents |
Antispasmodics & Motility Agents
| Drug | Mechanism | Use | Notes |
|---|
| Hyoscine butylbromide (Buscopan) | Anticholinergic (muscarinic M1/M3 antagonist) → smooth muscle relaxation → reduces biliary and GI spasm | Biliary colic, IBS, GI spasm | Not available in US (available in Canada/Europe); IV form used for biliary spasm perioperatively |
| Dicyclomine (Bentyl) | Anticholinergic → smooth muscle relaxant | GI/biliary spasm, IBS | Side effects: dry mouth, urinary retention, tachycardia, blurred vision, constipation (anticholinergic syndrome) |
Pain Management in Biliary Disease
| Drug | Use | Notes |
|---|
| NSAIDs (ketorolac, diclofenac) | Biliary colic — reduce prostaglandin-mediated gallbladder contraction and pain; may reduce risk of progression to cholecystitis | Ketorolac IV/IM for acute biliary colic in ER; effective as opioids for biliary colic in some studies; avoid in renal impairment |
| Opioids (morphine, hydromorphone, fentanyl) | Moderate-severe biliary pain | Morphine may increase sphincter of Oddi pressure (theoretical concern, but clinical significance questioned); meperidine historically preferred but now discouraged due to seizure risk from normeperidine metabolite |
| Antacids / PPIs | Concomitant GERD/dyspepsia often present with biliary disease; also preoperative | PPIs do NOT treat biliary disease directly; address coexisting acid reflux symptoms |
🎯 Boards PearlMorphine and sphincter of Oddi: classically taught that morphine causes sphincter of Oddi spasm → avoid in biliary colic; however, clinical evidence does not support avoiding morphine — use appropriate opioid for pain. Meperidine (Demerol) should be AVOIDED in biliary colic — the metabolite normeperidine is toxic (lowers seizure threshold), especially in renal impairment and elderly. Ketorolac is an excellent non-opioid option for acute biliary colic in the emergency setting.