Exam 4 GI + Pain Flashcards
Nociceptive pain
Nerve receptor stimulation following tissue injury, disease or inflammation
Neuropathic pain
Abnormal signal processes in the CNS, perceived as burning, tingling, shooting
Neurotransmitters involved in pain
Prostaglandins, histamine, bradykinin, serotonin
Main inhibitory neurotransmitters
Serotonin and norepinephrine
Acetaminophen
Prostaglandin inhibitor in CNS and COX3
No anti-inflammatory, platelet or GI effects
Decreases opioid requirements by 30%
Aspirin
Effective as APAP
Very effective in pain associated with inflammation
GI side effects
Irreversible inactivation of COX1 and COX2
COX1 inhibition
Leads to decreased blood flow to kidney, GI tract tissues and decreases platelet aggregation
COX2 inhibition
Decreases inflammation
Misoprostol (Cytotec)
Can decrease NSAID induced bleeding
Synthetic prostaglandin E analog parent drug rapidly de-esterified to misoprostol acid and replaces protective prostaglandins
Inhibits gastic acid secretions and protects gastric mucosa
Pregnancy category X
SE: diarrhea, abdominal pain, HA
Ketorolac (Toradol)
First parenteral NSAID available
Use limited to <5 day due to SE profile
Effects of opioids
Analgesia, respiratory depression, sedation, confusion, N/V, pruritus, miosis, constipation, urinary retention
Opioid DOC in renal or liver failure
Fentanyl
Fentanyl forms
Injectable, buccal, long acting transdermal patch (duration of 72 hours)
Causes less histamine release than other opioids
Tramadol
Centrally acting weak mu receptor agonist; also inhibits NE reuptake and increases serotonin release
Less respiratory depression
May increase risk of seizures
Methadone
Used to treat opioid substance abuse
Mu receptor agonist and NMDA receptor antagonist
8-12 hours duration if used chronically
Cheap and good for refractory pain
Naloxone
pure opioid antagonists
Used for opioid induced respiratory depression
Lasts 45 minutes
SE: tachycardia, htn, V Fib, cardiac arrest, seizures
Opioid treatments of constipation
Methylnaltrexone or naloxegel
Mu antagonism in gut only
Withdrawal symptoms of opioid use
Tremors, sweating, fever, flu like symptoms, increased RR, perspiration, lacrimation, mydriasis, anorexia
Co-analgesics
Antidepressents, anticonvulsants, sodium channel blockers, antispasmodics, antispastics
Antidepressants for pain relief
TCAs and SNRI
Good for neuropathic pain
Anticonvulsants for pain relief
Gabapentin, pregabalin, carbamezapine usually
Decrease activation of second order neurons responsible for pain transmission
Good for neuropathic pain
Sodium channel blockers
Act as local anesthetics
Block Na channels, slowing pain transmission and lowering firing threshold of second order neurons
Topical lidocaine patches indicated for postherpetic neuralgia
Ketamine
NMDA antagonist
Lower doses for analgesia, higher doses for anesthesia
Decreases sensitivity to pain impulses
SE: vivid dreams, sedation, delirium, hallucinations
Cyclobenzapine
Antispasmodic skeletal muscle relaxant
Mostly used for lower back pain
Has anticholinergic SE
Baclofen
Antispastic agent
Used for MS and spinal cord injuries
Hydromorphone
Dilaudid
More potent than morphine, safer in renal failure, more soluble
Good choice for opioid tolerant patients or cachectic patients
Codeine
Weak opioid activity by itself; usually combine with APAP
Metabolized to morphine by the liver
Ceiling effect on analgesia but not side effects
Meperidine
Demerol Not first line Short duration of action Low potency Very long half life Avoid in renal dysfunction or hx of seizures
Steroids useful for what type of pain
Bone pain and nerve compression
Dexamethasone and prednisone
Herb-drug interactions
- Taking Senna can affect drug transit time and reduce absorption of prescription medicines
- Zinc lozenges decrease levels of antibiotics
- High doses of vitamin E may increase anticoagulant effect of warfarin
- Taking ephedra with caffeine can cause death
Dronabinol + Nabilone
Both synthetic THC approved for treatment of N/V associated with cancer chemotherapy
SE: dry mouth, sedation, orthostatic hypotension, ataxia, dizziness, anxiety, tachycardia, agitation, confusion
Neurotransmitters involved with the vomiting center
Dopamine, histamine, serotonin, ACh
Antiemetic effects occur when these neurotransmitters are blocked
Phenothiazines
- MOA
- SE
- Uses
Prochlorperazine + Promethazine
Dopamine receptor blockade in chemo trigger zone
Has anticholinergic activity also
SE: drowsiness, sedation, increased EPS, CNS depression
Preg Category C
Monotherapy for mild-moderate N/V or long term therapy
Antihistamines
- MOA
- SE
- Uses
Hydroxyzine, meclizine, dimenhydrinate (dramamine), scopolamine
Interrupts visceal afferent pathways responsible for N/V
Can be used in pregnancy but not BF
Used for mild nausea such as motion sickness
SE: sedation, drowsiness, confusion, anticholinergic effects
CI: asthma, glaucoma, GI/urinary obstruction
Benzodiazepines for N/V
- MOA
- SE
- Uses
Lorazepam (ativan) most frequently used
Prevent/treat emesis as well as anxiolysis and amnesia
Helpful for anticipatory nausea/vomiting with chemo
SE: CNS depression, memory impairment, constipation, headache, change in appetite
CI: hepatic or renal failure
Pregnancy D
Serotonin antagonists
- MOA
- SE
- Uses
Ondansetron (Zofran), Granisetron, Palonestetron, Dolasetron
Antagonize 5HT3 receptors centrally in CTZ and peripherally at vagal and splanchnic afferent fibers
Used for chemo N/V or hyperemesis gravidarum primarily
SE: mild to moderate HA, diarrhea, increase in liver enzymes
CI in lactation
Does not cause EPS symptoms
Metoclopramide (Reglan)
- MOA
- SE
- Uses
Used for N/V related to diabetic gastric stasis, post surgical gastric stasis, GERD, migraine HA
Increases motility and gastric emptying
Dopamine receptor inhibition in CTZ
Sensitizes tissues to Ach
SE: EPS, diarrhea
Hypertensive crisis can occur when used with MAOI
Preg Cat B
Steroids for N/V
- MOA
- SE
- Uses
Reserved for chemo induced N/V
Dexamethasone + methylprednisolone most used
SE: mental disturbances, headaches, insomnia, restlessness, increase in glucose levels, immunosuppression, osteoporosis
Dronabinol
- MOA
- SE
- Uses
Cannibinoid
Administer 6-12 hours prior to chemo
SE: sedation, ataxia, dysphoria, orthostatic hypotension, blurred vision, tachycardia, appetite stimulation
Antacids
- MOA
- SE
- Uses
Mg, Al or Ca salts
Coat stomach with a neutralizing substance
For mild N/V
By increasing pH, pepsin is inhibited
1st line for non-chemo N/V
Ondansentron
Phenothiazine
Promethazine
2nd line for non-chemo N/V
Antihistamine/anticholinergic
1st line for acute emesis in chemo N/V
Combo of serotonin antagonist and steroids minutes before chemo
What is responsible for gastric mucosal damage
HCl and pepsin
What stimulates parietal cells to release acid
Histamine, ACh, gastrin
What decreases gastric acid production
Prostaglandins and bicarbonate
-H Pylori and NSAIDs impede these defenses
Effect of H Pylori
Increases acid production, gastric secretions and secretes noxious enzymes and toxins
H2 receptor antagonists
Cimetidine (tagamet), famotidine (pepcid), nizatidine, ranitidine (zantac)
Effective in mild GERD, ulcer healing, H Pylori eradication
Reversibly inhibits H2 on gastric pariertal cells, decreasing acid secretion and pepsin activation
Proton pump inhibitor
Omeprazole (Prilosec), Pantoprazole (Protonix)
Most potent acid-suppressing agent
Binds to H+/K+ ATPase in gastric parietal cells–causes decrease basal and stimulated acid secretion
Moderate to severe GERD, revention of NSAID induced ulcer, ulcer healing
Irreversibly inhibits gastric proton pumps
Category C pregnancy, CI in BF
SE: HA, N/V, abdominal pain, flatulence
Antibiotics used in H Pylori eradication
Amoxicillin, Clarithromycin, Metronidazole, Tetracycline, Misoprostol
Tx of NSAID induced ulcer
PPI for 4 weeks and D/C NSAID
Triple therapy for H Pylori
PPI, amoxicillin and clarithromycin for 7-10 days
OR
PPI, metronidazole and clarithromycin 10-14 days
2 step therapy for H Pylori
PPI and amoxicillin for 5 days followed by PPI, clarithromycin and metronidazole for 5 days
Bulk forming laxatives
- Examples
- MOA
- SE
- CI
Methylcellulose, psyllium (metamucil), polycarbopil, malt soup extract, wheat dextin
Non-digestible and non-absorbable
Binds to fecal contents and pulls water into stool–softens and lubricates stool
Take with plenty of water
Not systemically absorbed
SE: increased gas and bloating
CI: strictures of esophagus, GI ulcerations, stenosis
Hyperosmotic laxatives
- Examples
- MOA
- SE
- CI
Lactulose, sorbitol, polyethylene glycol (Miralax)/electrolyte solution, polyethyle glycol, magnesium hydroxide, magnesium citrate
Increases concentration of solutes, creating osmotic pressure by drawing more fluid into GI tract
Glycerine safest–use in children
SE: abdominal cramping and nausea
CI: diabetic patients and appendicities, fecal impaction or intestinal obstruction
Saline laxatives
- Examples
- MOA
- SE
- CI
MgOH, Mg Citrate, Mg Sulfate, Na phosphate
Draw water into intestines through osmosis
May cause dehydration
Stimulant laxatives
- Examples
- MOA
- SE
- CI
Bisacodyl (dulcolax) + Senna concentrates
Increases peristalsis through direct effects on smooth muscle of intestine and promotes fluid accumulation in colon
Avoid long term
SE: N/V, Cramping
Surfactant laxatives
- Examples
- MOA
- SE
- CI
Ducosate Sodium (colace)
Stool softeners–decrease surface tension of liquid contents of bowel by promoting additional lipid into the stool
Inhibits fluid and electrolyte reabsorption
DOC for patients who should not strain
Take with plenty of water
Lubricant laxatives
- Examples
- MOA
- SE
- CI
Mineral Oil, Castor oil
Oil coats and softens the stool and prevents reabsorption of water from stool by the colon
Prevents straining
SE: can impair absorption of fat soluble vitamins and unpleasant taste
Secreatagogues
- Examples
- MOA
- SE
- CI
Lubiprostone
Derivative of prostaglandin–increases chloride rich intestinal fluid without altering serum sodium and potassium
Acts locally on intestines
SE: nausea
CI: mechanical obstruction, severe diarrhea
Naloxegol
Peripherally acting mu-opioid receptor antagonists
May cause opioid withdrawal
SE: abdominal pain, diarrhea, nausea, flatulence, vomiting, headache, hyperidrosis
First line therapy for constipation
Bulk forming laxative
Then stool softener
1st line for avoiding straining
Stool softener
2nd line therapy for constipation
Milk of magnesia, lactulose, sorbitol (hyperosmotic laxatives)
Medications that can cause diarrhea
Antacids, antibiotics, SSRIs, cholinergic agents, colchicine, digoxin, metoclopramide, laxatives, metformin, prostaglandins, quinidine
Prophylactic agent for travelers diarrhea
Bismuth subsalicylates (Pepto bismol), quinolone antibiotic or tifaximin
Loperamide
Immodium
Opioid receptor agonist acting on mu receptors of large intestine
Avoid with infectious diarrhea–fever, blood in stool, fecal leukocytes SS
SE: dry mouth, abdominal discomfort, constipation, drowsiness
Diphenoxylate
Similar to loperamide but does cross BBB
Bismuth subsalicylates
Pepto Bismol
Stimulates prostalandin, mucus and bicarb secretion in stomach and inhibits prostaglandin and chloride secretion in large intestine
Caution if taking aspirin
SE: black stools, darkening of tongue, tinnitus
Kaolinide
Absorbs water along with bacteria and toxins as well as helps solidify stools
SE: constipation and feeling ful, bloating, gas
Works locally not systemically
Rifaximin
Semisynthetic antibiotic similar to rifampin
Only effective against noninvasive strains of E Coli
Use for travelers diarrhea
SE: peripheral edema, nausea, dizziness, fatigue, muscle spasms
1st line for diarrhea
Loperamide or rifaximin
2nd line for diarrhea
Adsorbents
Antispasmodics for IBS
- Examples
- MOA
- SE
- CI
Dicyclomine (Bentyl) and Hyosycamine
Blocks effects of ACh at muscarinic cholinergic receptors–has anticholinergic effects
Direct relaxation of smooth muscle component of GI tract
SE: dry mouth, vomiting, dysphagia, urinary retention
CI: glaucoma, stenosing peptic ulcer, COPD, cardiac arrhythmias, impaired liver or kidney, MG
Pregnancy category B, CI in lactation
Alosetron
Serotonin 3 receptor antagonist
Decreases abdominal pain, slows colonic transit time, increases stool consistency
Used for severe diarrhea IBS
1st line tx for IBS
Tx Should only be used in exacerbations Contipation: Osmotic laxative Diarrhea: loperamide Bloating and pain: Dicyclomine Psychological symptoms: SSRI
Treatments for inflammatory bowel disease
Aminosalicylates, corticosteroids, immunosuppresive agents, antibiotics, biologic agents
Aminosalicylates
Sulfasalazine, mesalamine, olsalazine, balsalazide
Gold standard for tx of UC or CD
Decrease inflammation of GI tract by inhibiting prostaglandin synthesis
May improve symptoms within 1 week
CI in aspirin allergy
May need to take long term
Corticosteroids for inflammatory bowel disease
Prednisone, methylprednisone, hydrocortisone, dexamethasone, budesonide
Used for acute IBD exacerbations only
Causes immunosuppression and prostaglandin inhibition when UC/CD fails to respond to aminosalicylates
Immunosuppresive agents for inflammatory bowel disease
Azathioprine, 6-mercaptopurne, methotrexate, cyclosporine
Used as adjunct therapy to induce and maintain remission
Abx for inflammatory bowel disease
Metronidazole or ciprofloxacin
Must be active against G- and mycobacterium
1st line tx for CD
Mild to moderate: aminosalicylate alone or in combo with antibiootic or budesonide monotherapy oral
Moderate to severe: combo of aminosalicylates .+ steroids
Aminosalicylate of choice
Mesalamine
6-16 pills per day
Acute diarrhea
48 hours or less
Nonpharmacologic measures and adequate hydration; avoid anti diarrheals if possible
If using an anti-diarrheal, adsorbents are best
Aminosalicylates
Sulfasalazine, mesalamine, olsalazine, balsalazide
Gold standard for tx of UC or CD
Decrease inflammation of GI tract by inhibiting prostaglandin synthesis
May improve symptoms within 1 week
CI in aspirin allergy
Corticosteroids for inflammatory bowel disease
Prednisone, methylprednisone, hydrocortisone, dexamethasone, budesonide
Used for acute IBD exacerbations only
Causes immunosuppression and prostaglandin inhibition when UC/CD fails to respond to aminosalicylates
Immunosuppresive agents for inflammatory bowel disease
Azathioprine, 6-mercaptopurne, methotrexate, cyclosporine
Used as adjunct therapy to induce and maintain remission
Abx for inflammatory bowel disease
Metronidazole or ciprofloxacin
1st line tx for CD
Mild to moderate: aminosalicylate alone or in combo with antibiootic or budesonide monotherapy oral
Moderate to severe: combo of aminosalicylates .+ steroids
Aminosalicylate of choice
Mesalamine
6-16 pills per day
Acute diarrhea
48 hours or less
Nonpharmacologic measures and adequate hydration; avoid anti diarrheals if possible
Chronic diarrhea
10 days
Opiates and opioid derivatives best
