© palliativedrugs.com Ltd. 1: GASTRO-INTESTINAL SYSTEM Antacids ........................................................ 1 Lactulose.................................................. 32 Alginate products ..................................... 2 Polyethylene glycol (macrogol) .......... 33 Simethicone................................................ 3 Magnesium salts ..................................... 34 Antimuscarinics ........................................ 5 Rectal products ...................................... 35 Hyoscine (scopolamine) Products for hemorrhoids ................ 37 butylbromide ........................................... 11 Pancreatin .................................................38 Prokinetics ................................................ 13 H 2 -receptor antagonists ..................... 15 Guidelines: Management of Misoprostol ............................................... 18 death rattle (noisy respiratory Proton pump inhibitors ...................... 19 secretions) .................................................10 Loperamide .............................................. 22 Guidelines: Opioid-induced Laxatives .................................................... 24 constipation .............................................. 26 Psyllium husk .......................................... 28 Guidelines: Bowel management Contact (stimulant) laxatives .............. 29 in paraplegia and tetraplegia ........... 27 Docusate sodium ................................... 31 ANTACIDS Antacids taken by mouth to neutralize gastric acid include: . magnesium salts . aluminum hydroxide . calcium carbonate . sodium bicarbonate. Magnesiumsalts are laxative and can cause diarrhea; aluminum salts constipate. Most proprietary antacids contain amixtureof magnesium salts and aluminum salts so as to have aneutral impact on intestinal transit. With doses of 4 100–200mL/24h, the effect of magnesium salts tends increasingly to override the constipating effect of aluminum. 1 The sodium content of some antacids maybedetrimental in patients on salt-restricted diets, e.g. those with hypertension or heart failure; Gaviscon. R Liquid (available OTC) contains Naþ 53mg/5mL (equivalentto4.6mmol/10mL dose) compared with 0.1nmol/10mL in aluminum hydroxide- magnesium hydroxide suspension (e.g. Almagel. R ). Regular use of sodium bicarbonate maycause sodium loading and metabolicalkalosis. Calcium carbonate maycause rebound acid secretion about 2h after each dose, and regular use maycause hypercalcemia, particularly if taken with sodium bicarbonate. Aluminum hydroxide binds dietaryphosphate.Itisofbenefit in patients with hyper- phosphatemiainrenal failure. Long-term complications of phosphate depletion and osteomalacia are not an issue in advanced cancer. In post-radiation esophagitisand candidosis which is causing painful swallowing, an aluminum hydroxide- magnesium hydroxide suspensioncontaining oxethazine,alocal anesthetic, can be helpful. Give5–10mL (without fluid) 15min a.c. &atbedtime, and p.r.n. beforedrinks. This should be regarded as short-term symptomatic treatment while time and specific treatment of the underlying condition permits healing of the damaged mucosa. Alternatively, lidocaine viscous oral suspension 2% (or acompounded lidocaine suspension) can be used (see p.449). The following should be borne in mind: . the administration of antacids should be separated from the administration of EC tablets; direct contact between EC tablets and antacids mayresult in damage to the enteric coating with consequential exposureofthe drug to gastric acid, and of the stomach mucosa to the drug . except for sodium bicarbonate,antacids delaygastric emptying and maythereby modify drug absorption. CPCF 1 © palliativedrugs.com Ltd. © palliativedrugs.com Ltd. ALGINATE PRODUCTS . most antacid tablets feel gritty when sucked; some patients dislikethis . R . some proprietaryproducts are fruit-flavoured, e.g. Tu ms (chewable tablet) . R . the cheapest single-ingredient product is aluminum hydroxide chewable tablets (Amphojel ) . the cheapestsingle-ingredient magnesium product is milk of magnesia liquid (generic), containing magnesium hydroxide 80mg/mL . the cheapest aluminum- magnesium combinationproduct is ageneric storebrand liquid product . some antacids contain additional substances for use in specific situations, e.g. alginates (see below), simethicone (see p.3) . magnesium-containing antacids should be used with caution in patients with renal impairment (see p.491); calcium carbonate is preferable. Antacids are now generally only used p.r.n. for occasionaldyspepsia; H 2 -receptor antagonists (see p.15) and PPIs (see p.19) are used when continuous gastric acid reduction is indicated.2 Supply See also Simethicone ,p.3. Aluminum hydroxide Amphojel. R (Aurium Pharma) Tablets chewable 600mg, 28 days @1t.i.d. &atbedtime ¼ $27; mint flavour. Oral suspension (sugar-free) 320mg/5mL,28days@10mL t.i.d. &atbedtime ¼ $38; mint flavour. Aluminum hydroxide- magnesium hydroxide Almagel 200. R (Laboratoire Atlas) Oral suspension (sugar-free) aluminum hydroxide 200mg, magnesium hydroxide 200mg/ 5mL, 28 days @10mL t.i.d. &atbedtime ¼ $13; low Naþ . Calcium carbonate Tu ms. R (GlaxoSmithKline) Tablets chewable regular strength, 500mg; extra strength, 750mg; ultra strength, 1,000mg; 28 days @2t.i.d. &atbedtime ¼ $7, $13 and $19 respectively; low Naþ ,fruit flavour. With oxethazine Mucaine. R suspension (Aurium Pharma) Oral suspension aluminum hydroxide 300mg, magnesium hydroxide 100mg, oxethazine 10mg/5mL,28days@10mL t.i.d. a.c. &atbedtime ¼ $77. 1Morrissey Jand Barreras R(1974) Antacid therapy. New England Journal of Medicine. 290:550–554. 2NICE (2004) Dyspepsia. Management of dyspepsia in adults in primarycare. In: Clinical Guideline 17.National Institute for Clinical Excellence. Available from: www.nice.org.uk/page.aspx?o¼ CG017 ALGINATE PRODUCTS Included for general information. Alginate products are generally not recommended as antacids for palliativecarepatients. Class: Alginate. Indications: Acid reflux (‘heartburn’). Pharmacology Antacid products containing alginic acid or sodium alginate preventesophageal reflux pain by forming an inert low-densityraft on the top of the acidic stomach contents. Both acid and air bubbles are necessarytoproduce the raft. Compoundalginate products maythus be less effective if used with drugs which reduce acid (e.g. an H 2 -receptor antagonist or aPPI) or products which reduce air bubbles (i.e. an antifoaming agent/antiflatulent). 2www.palliativedrugs.com © palliativedrugs.com Ltd. © palliativedrugs.com Ltd. SIMETHICONE Gaviscon. R Liquid, asodium alginate product, is aweak antacid; most of the antacid content adheres to the alginate raft. This neutralizes acid which seeps into the esophagus around the raft but does nothing to correct the underlying causes, e.g. lax lower esophagealsphincter, hyperacidity,delayed gastric emptying, obesity.Indeed, alginate-containing products arenobetter than simethicone-containing antacids in the treatment of acid reflux.1 Compound alginate products have been largely superseded by acid suppression with PPIs and H 2 -receptor antagonists. Onset of action 5 5min. Duration of action 1–2h. Cautions Gaviscon. R Liquid contains Naþ 53mg/5mL (equivalentto4.6mmol/10mL dose). It should not be used in patients requiring asalt-restricted diet, e.g. those with fluid retention, heart failureor renal impairment. Dose and use Several products are available but none is recommended.For patients already taking an alginate product and who are reluctant to change to aluminum hydroxide– magnesium hydroxide (or similar option), and if thereare grounds for limiting sodium intake, choose one with alow sodium content, e.g. Gaviscon Heartburn Relief Tablets. R (22mg Naþ /tablet). Supply Gaviscon. R Liquid and tablets are available OTC. Gaviscon Liquid. R (GlaxoSmithKline) Oral suspension (sugar-free) sodium alginate 250mg, aluminum hydroxide 100mg/5mL, 340mL bottle ¼ $13 and 600mL bottle ¼ $20; 53mg Naþ /5mL. Gaviscon Heartburn Relief Tablets. R (GlaxoSmithKline) Tablets chewable alginic acid 200mg, magnesium carbonate 40mg, 100 tablets ¼ $20; 22mg Naþ /tablet. Gaviscon Heartburn Relief Extra Strength Tablets. R (GlaxoSmithKline) Tablets chewable alginic acid 313mg, magnesium carbonate 63mg, 60 tablets ¼ $20; 35mg Naþ /tablet. MaaloxNighttime. R (Novartis) Oral suspension sodium alginate 275mg, calcium carbonate 300mg, magnesium carbonate 125mg/5mL,350mL bottle ¼ $12; 45mg Na/ 5mL, mint flavour. 1PokornyCet al. (1985) Comparison of an antacid/dimethiconemixture and an alginate/antacid mixture in the treatment of oesophagitis. Gut. 26:A574. SIMETHICONE Class: Antifoaming agent (antiflatulent). Indications: Acid dyspepsia (including acid reflux), gassy dyspepsia, † hiccup (if associated with gastric distension). Pharmacology Simethicone(silica-activated dimethicone or dimethylpolysiloxane) is amixtureofliquid dimethicones with silicon dioxide. It is an antifoaming agent present in several single-agent products (e.g. Ovol. R )and some combinationantacids (e.g. Diovol Plus. R and Maaloxantacid with anti-gas. R ). By facilitating belching, simethicone eases flatulence, distension and postprandial gastric discomfort. Simethicone-containing antacids are as effectiveasalginate-containing CPCF 3 © palliativedrugs.com Ltd. © palliativedrugs.com Ltd. SIMETHICONE products in the treatment of acid reflux.1 Simethicone-containing antacids should be used in preferenceto alginate products because they are moreeffectiveantacids, are cheaper,and