Pharm Flashcards
What is the MOA of and indication for loperamide?
- Binds Mu opioid receptors in the gut wall.
- Also reduces ACh/prostaglandin release.
- Both actions decrease GI motility.
Used to treat common diarrhea.
What are some AE of loperamide?
QT prolongation/Torsade’s
Constipation, dizziness, nausea
What is the MOA of and indication for bismuth-subsalicylate?
- Stimulates absorption of water from the LI.
- Forms a protective lining in the intestines
- Believed to have some antimicrobial properties
Used to treat common diarrhea and H. pylori infections. (Pepto-Bismol)
What are some AEs of bismuth-subsalicylate?
Dark stools
Dark tongue
**AVOID USE in patients with renal dysfunction: bismuth can accumulate and cause CNS effects, though this is rare
What is the MOA of and indication for diphenoxylate/atropine?
Diphenoxylate/atropine is an opioid analgesic.
- Binds mu opioid receptors in the GI tract (decreases motility and secretions).
- Atropine reduces risk of abuse
Diphenoxylate/atropine is used to treat common diarrhea. It is not used frequently, as loperamide is equally effective.
What are some AEs of diphenoxylate/atropine?
Well, it’s an opioid.
N/V, respiratory depression, sedation, miosis, confusion
Anticholinergic effects can also occur (anti-SLUD effects).
What is the MOA of and indication for opium tinctures?
Opium tinctures bind mu opioid receptors in the GI tract, decreasing peristalsis and secretions.
It is (rarely) used for severe diarrhea; sometimes used in HIV patients with crypto.
What are some AEs of opium tinctures?
It’s opium?
N/V, respiratory depression, sedation, miosis, confusion, addiction.
Schedule II drug.
Name four therapies for common diarrhea that we discussed.
- Loperamide (OTC)
- Bismuth-subsalicylate (OTC)
- Diphenoxylate/atropine (Rx)
- Opium tincture (Rx)
What are nine drug classes we discussed for treatment of IBS with constipation?
- Bulk-forming laxatives
- Osmotic laxatives
- Stool softeners
- Lubricants/emollients
- Stimulants
- Prostaglandin derivatives
- Guanylate cyclase-C receptor agonists
- Na+/H+ exchanger inhibitors
- 5-HT4 agonists
What is the MOA of and indication for psyllium (or methylcellulose, or fiber)?
These are examples of bulk forming laxatives.
They hold water content in the intestine, forming a softer/bulkier stool that is easier to pass.
They are used to treat constipation.
What are some examples of osmotic laxatives? What is their MOA?
Lactulose, macrogol, and magnesium are examples of osmotic laxatives. They are non-absorbable and create a hypertonic environment inside of the colon, drawing water in, “flushing” out the colon.
They are used to treat constipation.
What kind of drug is lubiprostone? What is its MOA and indication?
Lubiprostone is a prostaglandin derivative used to treat constipation.
It activates Cl- channels in the GI tract, stimulating intestinal fluid secretion.
What is the MOA of and indication for linaclotide?
Linaclotide is used to treat IBS-C in adults. It works by targeting guanylate cyclase-C receptors, increasing concentrations of cGMP. cGMP then activates CF-regulated ion channels, increasing GI motility and secretions.
Plecanatide is a similar drug.
What is the MOA of and indication for plecanatide?
Plecanatide is used to treat IBS-C in adults, as long as there is no GI obstruction.
It works by targeting guanylate cyclase-C receptors, increasing concentrations of cGMP. cGMP then activates CF-regulated ion channels, increasing GI motility and secretions.
Linaclotide is a similar drug.
What is the MOA of and indication for tenapanor?
Tenapanor is used to treat IBS-C in adults. It may also be used to treat hyperphosphatemia in CKD patients.
It works by inhibiting Na+/H+ exchanger 3. Inhibition of sodium absorption results in decreased water absorption, decreasing transit time.
What is the MOA of and indication for tegaserod?
Tegaserod is used to treat IBS-C in women <65 YO without cardiovascular risk.
It works via agonism of 5-HT4 receptors: these stimulate GI secretions and speeds transit.
Name 3 agents that directly increase intestinal peristalsis.
Cascara sagrada
Bisacodyl (dulcolax)
Senna
(^Stimulants are often abused by patients with eating disorders, and should not be prescribed for chronic use.)
What are some AE associated with bulk-forming laxatives?
Flatulence
Bloating
Must take with adequate hydration or intestinal blockage can occur
What are some AE associated with osmotic laxatives?
Generally well-tolerated
Diarrhea
Mg can accumulate in patients with renal impairment
What are some AE associated with lubiprostone?
Diarrhea
Nausea
Dyspnea
Must adjust dose in patients with hepatic impairment
What are some AE associated with guanylate-cyclase agonists?
(Linaclotide, plecanatide) Diarrhea (can be severe) Flatulence Abdominal pain Abdominal distention Serious dehydration can occur (BBW for patients <18YO)
What are some AE associated with tenapanor?
Diarrhea Flatulence Abdominal distention Dizziness Serious dehydration (BBW for patients <18YO)
What are some AE associated with tegaserod?
Diarrhea Flatulence Dizziness Dyspepsia Abdominal pain HA Rare reports of suicidal ideation
Contraindications: hx of MI, stroke, TIA, angina, ischemic colitis, renal impairment, hepatic impairment
What are 7 drug classes commonly used to treat IBS-D?
- Anti-diarrheals (loperamide)
- Antispasmodics
- Antidepressants
- Antibiotics (rifaximin specifically)
- Bile acid sequestrants
- Opioid receptor agents
- 5-HT3 receptor antagonists
What is the MOA of and indication for hyoscyamine?
Hyoscyamine is an antispasmodic used in the treatment of IBD-D. Often used PRN or before meals.
It relaxes intestinal smooth muscle (directly and via anticholinergic mechanisms).
Dicyclomine is a drug in the same class.
What is the MOA of and indication for dicyclomine?
Dicyclomine is an antispasmodic used in the treatment of IBD-D. Often used PRN or before meals.
It relaxes intestinal smooth muscle (directly and via anticholinergic mechanisms).
Hyoscyamine is a drug in the same class.
What are some AE associated with dicyclomine and hyoscyamine?
Anticholinergic effects:
- Anti-SLUD (salivation, lacrimation, urination, defecation)
- Drowsiness*
- Dizziness
- Confusion
- Palpitations
- Visual disturbance
What is the MOA of and indication for amitriptyline?
Amitriptyline is a tricyclic antidepressant used in the treatment of moderate to severe IBD-D, especially if there is an anxious/depressive element to their disease.
It works via anticholinergic effects to reduce abdominal pain and alter GI transit time.
What are some AE associated with amitriptyline?
Anticholinergic effects:
- Anti-SLUD (salivation, lacrimation, urination, defecation all dry up)
- Drowsiness*
- Dizziness
- Confusion
- Palpitations
- Visual disturbance
- Overdose is quite dangerous; can cause cardiac arrhythmias
What is the MOA of and indication for Rifaximin?
Rifaximin is an antibiotic that is often used to treat IBD-D. It is often used in patients with hepatic encephalopathy.
It is thought to alter gut microbiota. Specifically, it reduces population of bacteria that absorb nitrogen.
What are some AE associated with rifaximin?
- Antibiotic resistance and associated C. diff
- Nausea
- Myalgia
- Elevated ALT
- Elevated creatinine kinase
What is the MOA of and indication for cholestyramine?
Cholestyramine is a bile acid sequestrant. It decreases absorption of triglycerides and cholesterol. It is used off-label to improve IBS-D symptoms and slow motility. Data are limited.