Ch 70: Constipation and Diarrhea Flashcards
med conditions that cause constipation
IBS-C, anal disorders, MS, cerebrovascular events, PD, spinal cord tumors, DM, hypothyroid
lifestyle measures for constipation
64 oz water daily, limit caffeine/etoh d/t dehydration, inc physical activity. replace refined foods with whole grains and foods high in fiber.
drugs that cause diarrhea
antacids with Mg, abx or CDAD, antineoplastics, colchicine, laxatives, metoclopramide, misoprostol, quinidine
diarrhea common causes
bacterial - e. coli. r/o lactose intolerance. viral resolves in few days without tx. food poisoning or eating/drinking contamination
drug tx diarrhea
short term bismuth subsalicylate (pepto bismol) has antisecretory and antibacterial effects, or loperamide (antimotility agent that slow GI and prolong water absorption)
non drug tx diarrhea
fluid and ‘lyte replacement. replace fuids with PO rehydration solns (pedialyte, infalyte, etc) or gatorade as alt.
diarrhea assoc with IBS
imodium usually acceptable. rifaximin (xifaxan) is abx approved for IBS-D but costly and relapse usually within several mo of tx. alosetron (lotronex) useful for women only, restricted d/t risk of ischemic colitis. pain/abd discomfort managed with antispasmodics and antidepressants.
peripherally acting mu opioid agonist - example, schedule, indication
eluxadoline (Viberzi), CIV, REMS. indication: IBS-D where D is difficult to treat with usual tx. acts like opioid to induce constipation, but does not cross CNS.
pepto-bismol - generic, contraindications, ADRs.
bismuth subsalicylate. contraindications: salicylate allergy, use with other salicylates (ASA, NSAIDs), coagulopathy, black/tarry stool. ADRs: black tongue/stool. caution in children d/t reye syndrome.
imodium - generic, dosing, notes
loperamide. 4 mg PO after 1st loos stoll then 2 mg after each subsequent loose stool. max 16 mg/d. self tx should not be >48 h
lomotil - generic, schedule, max dose
diphenoxylate/atropine. max 20 mg/d. subtx amt of atropine included to discourage abuse. CV
dicyclomine - brand, warnings, ADRs, MOA, indication
bentyl. antispasmotic. warnings: AntiACh. ADRs: dizziness, dry mouth, nausea, blurred vision. indication: abd discomfort in diarrhea or constipation with IBS
AGA guidelines for constipation
inc fiber intake via diet or supplement (1st line and for preg), add osmotic agent or stool softener which is OTC.
bowel prep
prior to colonoscopy. sodium phosphates (fleet enema, osmoprep) can cause fluid/lyte abnormalities, risk with renal or cardiac disease. PEG formulations. use extra caution with CVD, renal insufficiency, and with concomitant diuretics.
bulk forming agents - examples, MOA, notes
psyllium (metamucil), calcium polycarbophil (fibercon), methylcellulose (citrucel). create gel like matrix in stool to soak up fluid in loose stool and add bulk to stool. take 2 h before/after other drugs. requires adequate fluid.
osmotics - examples, MOA, ADRs, notes
Mg hydroxide (MOM), PEG 3350 (miralax), glycerin (pedia-lax). ADR: lyte imbalance. MOA: cause fluid to retain in bowel wiht net inc of fluid secretions in small intestines to distend colon and inc peristalsis. Caution with Mg in renal impairment. onset is 30 min PO. suppository used for children who need to defecate.
stimulants - examples, MOA, notes
senna (senokot), bisacodyl (dulcolax). MOA: stimulates the colonic neurons for peristaltic activity. give 30 min after meal. onset is 6-12 h oral. usually needed with chronic opioids. “push”
emollients - example, MOA, notes
docusate (colace). MOA: soften fecal mass by reducing surface tension of oil-water interface of stool to allow more water and fat to mix with stool and make defecation easier. preferred when straining should be avoided (postpartum, post-MI, anal fissures, hemorrhois). use when stool is hard/dry. “mush”
lubricants - example, MOA, notes
mineral oil. MOA: coat bowel and stool mass with water proof film to keep moisture in stool to defecate easier. onset 6-8 h. generally not rec d/t safety like aspiration (lipid pneumonitis)
osmotics for whole bowel irrigation
PEG (colyte, gavilyte, golytely, etc). contraindications: acute phosphate nephropathy, gastric bypass or stapling surgery. consume prior to colonoscopy along with “clear liquid diet”. counsel to not consume red/blue/purple food coloring, solid or semi solid foods. some brands need medguide.
lubiprostone - brand, MOA, ADRs, indication
amitiza. activates Cl channels in GI to inc fluid in GI and peristalsis. ADRs: ND, HA. consider alt if pt on methadone. indicated in CIC, opioid induced constipation, IBS-C in women.
linaclotide - brand, MOA, BBW, ADRs, notes, indication
linzess. agonist of guanylate cyclase C to inc Cl and bicarb secretion into GI to dec GI transit time. BBW: death d/t dehydration in animals, avoid in peds. ADRs: diarrhea. keep in original container, medguide. indication: CIC in adults, IBS-C in adults
alvimopan - brand, MOA, BBW, contraindications, indication
entereg. peripherally acting mu opioid antagonist to dec constipation. BBW: potential risk of MI with long-term use. contraindications: pts who have taken tx dose of opioids for 7+ days before use. indications: post-surgical pts to dec risk of post-op ileus. inpt only. REMS drug.
plecanatide - brand, indication, BBW, ADRs, notes
trulance. agonist of guanylate cyclase C to inc Cl and bicarb secretion into GI to dec GI transit time. BBW: death d/t dehydration in animals, avoid in peds. ADRs: diarrhea. indication: CIC in adults.
