Adult IBS meds

Question 1

Chloride Channel Activator for IBS

Answer 1

Example: Lubiprostone

MOA: Increase chloride in intestinal secretions with changing chloride/potassium
balance; softens stool, increases GI motility.

Dosage: 8 mcg BID

Used for IBS-C in adults. Take with food to decrease nausea. Report diarrhea.

Question 2

Anticholinergic / Antispasmodic for IBS

Answer 2

Example: Hycosamine, Dicyclomine HCL

MOA: Hycosamine decreases GI spasms
Dicyclomine decreases GI motility and GI tone

Dosage:
Hycosamine 0.125 mg 30—60 min before meals; max
dose 1.5 mg/24 hr.

Dicyclomine 10—20 mg tid to qid, max dose of 160
mg/day.

Antacids decrease drug absorption; take them at least 1 hr after taking hyoscyamine.

Assess for urinary retention and constipation. Take Dicyclomine 30 min—l hr before meals.

Question 3

Antidepressants for IBS

Answer 3

Example: Amitriptyline

MOA: Antidepressant and anticholinergic effects

Dosage: Up to 75 mg/day in divided doses

May be helpful for some patients with IBS. Take 30-40 min before meals.

Question 4

Antibiotics for IBS

Answer 4

Example: Rifaximin

MOA: Decreases bloating and distention of IBS, decreases diarrhea severity.

Dosage: 550 mg TID for 14 days

Off label use for IBS-D; at risk for C. difficile up to several weeks after use.

Question 5

Antidiarrheals for IBS

Answer 5

Example: Loperamide

MOA: Inhibits peristalsis, decreases volume
and increases viscosity of feces; decreases fluid and
electrolyte loss associated with diarrhea.

Dosage: 4 mg initial dose; 2 mg following each
loose stool up to 8 mg/day (OTC) and 16 mg/day if prescribed.

IBS-D; may cause dry mouth; take only as directed and instruct not to exceed recommended dose.

Question 6

Fiber supplements for IBS

Answer 6

Example: Psyllium

MOA: Increase bulk of stool

Dosage: I tsp or I packet in cold water 1—3 times a day.

Used for IBS-C. Indicated for short-term use.

Question 7

Serotonin 5 HT3 Antagonist for IBS

Answer 7

Example: Alosetron HCL

MOA: Blocks serotonin receptors to decrease pain perception in the GI tract, decreased GI motility, and increases transit time of colon contents

Dosage: Initial: 0.5 mg bid to 1 mg bid
Maintenance: 0.5mg to 1 mg daily

Used for IBS-D: women only.
Black box Warning: discontinue with symptoms of constipation or ischemic colitis.