Lax Pharm Flashcards
Name and describe the 3 types of primary constipation.
- Dyssynergic Defecation: pelvic floor muscle coordination loss
- Slow Transit: impaired peristalsis and GI reflexes
- Normal Transit: hard stool and perception of constipation
What is a Sitz marker study?
Patient ingests a capsule with 24 metal markers. The patient is then X-rayed periodically over the course of 5 days to measure peristaltic activity in the GI tract.
Methylcellulose
MOA: Bulk forming laxative (allows stool to retain more water)
Use: constipation
Contraindicated: pts. with PKU
Calcium Polycarbophil
MOA: Bulk forming laxative (allows stool to retain more water)
Use: constipation
Drug Interactions: anticoagulants, diuretics, antibiotics
Psyllium
MOA: Bulk forming laxative (allows stool to retain more water)
Use: constipation
Adverse Effects: bronchospasm
Magnesium Citrate
MOA: Osmotic diuretic, prevents absorption of ions in the GI tract to increases lumen osmolarity
Use: constipation
Contraindication: Chronic kidney disease or renal failure
Sodium Phosphate
MOA: Osmotic diuretic, prevents absorption of ions in the GI tract to increases lumen osmolarity
Use: constipation
Adverse Effects: acute phosphate neuropathy
Lactulose
MOA: synthetic sugar that cannot be absorbed by the GI tract to increase GI lumen osmolarity
Use: constipation
Adverse Effects: abdominal cramps, bloating
Polyethylene Glycol
MOA: osmotic laxative
Use: constipation
Adverse Effects: abdominal bloating, cramping
Senna
MOA: contains anthraquinone derivatives which irritate and stimulate the smooth muscle of the GI tract increase peristalsis.
Use: constipation
Adverse Effects: hypokalemia and protein malabsorption
Bisacodyl
MOA: stimulates peristalsis in the GI tract
Use: constipation
Adverse Effects: hypokalemia and protein malabsorption
Emollient
MOA: retains water in the intestinal lumen and lubricates the mucosa
Use: constipation
Adverse Effects: vomiting with aspiration of lipids leading to lipid pneumonitis
Lubiprostone
MOA: increases chloride channel activation and secretion of water into the intestines.
Use: constipation
Adverse Effects: nausea
Linaclotide
MOA: activates guanylate cyclase C, stimulates cGMP and stimulates intestinal secretion and motility
Use: constipation
Contraindication: peds patients under 6 years
Methylnaltrexone
MOA: selective opioid receptor antagonist used for opioid-induced constipation
Use: constipation
Contraindications: GI obstruction
How is clindamycin associated with diarrhea?
Most common antibiotic associated with overgrowth of C. diff
Bismuth Subsalicylate
MOA: anti-secretory in intestines and antimicrobial
Use: traveler’s diarrhea
Contraindications: do not use in patients with flu or chicken pox due to risk of Reye Syndrome
Loperamide
MOA: opioid agonist, slows peristalsis
Use: diarrhea (acute and chronic)
Contraindications: risk of toxic megacolon in AIDS patients.
Lomotil (Diphenoxylate + Atropine)
MOA:
Diphenoxylate-opioid agonist, inhibits excessive GI motility and secretion
Atropine-prevents abuse of the drug
Use: diarrhea
Adverse Effects: opioid withdrawal effects when removed (tachycardia, confusion, depression, dizziness, drowsiness, euphoria, flushing, headache), can lead to abuse
Motofen (Difenoxin + Atropine)
MOA:
Difenoxin-opioid agonist, inhibits excessive GI motility and secretion
Atropine-prevents abuse of the drug
Use: diarrhea, IBS, hyperhidrosis
Adverse Effects: CNS depression, dizziness, drowsiness, lightheadedness, headache, nausea, vomiting
Opium
MOA: binds opioid receptors to suppress GI secretions and motility
Use: diarrhea
Adverse Effects: CNS depression, palpitation, dizziness, drowsiness, constipation
Colesevelam
MOA: binds bile intestinal bile acids
Use: bile acid diarrhea, hypercholesterolemia, diabetes mellitus type 2
Contraindications: biliary or bowel obstruction
Octreotide
MOA: somatostatin analog used to inhibit intestinal motility
Use: diarrhea caused by: HIV, chemo, diabetes, hormone secreting tumors
