IBS-C Medication

psyllium, polycarbophil, methylcellulose

examples of bulk forming laxatives

Bulk Forming laxatives

• similar to dietary fiber

• trial of high-fiber diet should be continues for at least 1 month

• most patients begin to notice effects on bowel function 3 to 5 days after beginning a high-fiber diet

• should be taken with plenty of fluid to avoid choking

abdominal distension and flatus

ADR of bulk forming laxatives

senna, bisacodyl

stimulant laxatives

stimulant laxatives

• MOA: stimulate mucosal nerve plexus of the colon. May also increase intestinal fluid secretion

• cause a bowel movement within 8-12 hours of use

may cause severe abdominal cramping and electrolyte imbalances

ADR of stimulant laxatives

cholestyramine, colestipol, colesevelam

examples of bile acid sequestrants

bile acid sequestrants

• excess bile acids cause diarrhea by stimulating colonic secretion and motility

• MOA: bind with bile acids to form an insoluble complex that is eliminated in the stool

• most are given 2 g in 1-2 doses

• give with meals

polyethylene glycol (PEG)

example of osmotic agents

osmotic agents

• MOA: cause water retention in the stool; thereby increasing stool frequency

• indication: FDA-approved for treatment of constipation at low doses and is expected to produce a bowel movement in 1-3 days

• considered 2nd line if fiber supplementation is insufficient

  **PEG with electrolytes is used for bowel cleansing

nausea, vomiting, flatulence, and abdominal cramping

ADRs of osmotic agents

lubiprostone, linaclotide, plecantide, tenapanor

examples of intestinal secretagogues

lubiprostone (amitiza)

• MOA: Cl- channel activator that acts locally in the gut to open chloride channels on the GI luminal epithelium, which, in turn, stimulates chloride-rich fluid secretion into the intestinal lumen. Increased intraluminal fluid secretion helps to soften stool and accelerates GI transit time

• uses: chronic idiopathic constipation and opioid induced constipation

• contraindications: known or suspected mechanical GI obstruction

• ADR: headache, nausea, diarrhea

linaclotide (Linzess)/Plecanatide (Trulance)

• MOA: minimally absorbed peptide agonist of the guanylate cyclase-C receptor that stimulates intestinal fluid secretion and transit

• indication: approved for treatment of chronic idiopathic constipation

• L: 290 mg daily, P: 3 mg daily

• administer at least 30 minutes before the first meal of the day on an empty stomach

• ADRs: diarrhea (16-22%), diarrhea may occur after administration with a high fat breakfast, abdominal pain, flatulence

• Contraindications: known or suspected mechanical GI obstruction <2 yrs of age

• box warning: dehydration in kids <2 years (L) and <6 years (P)

Tenapanor (Ibsrela)

• MOA: sodium/hydrogen exchanger 3 (NHE3) inhibitor

• administer immediately prior to breakfast or the first meal of the day and immediately prior to dinner

• indication: IBS- constipation

• last line after lubiprostone, linaclotide, plecanatide

• ADRs: diarrhea, dizziness, flatulence, abdominal distension, abnormal bowel sounds, rectal hemorrhage

• Contraindication: known or suspected mechanical GI obstruction <6 years of age

• monitoring: serum potassium in patients with renal dysfunction

• box warning: risk of dehydration in pediatric patients