Lecture 9 Flashcards
1
Q
Overall purpose of the GI system
A
Digest and absorb nutrients from the foods and fluids we ingest
2
Q
Gastric glands
A
Glands in the stomach that are made up of many different cells
3
Q
Parietal cells:
A
- Secrete HCL
- Includes the proton pump
- Proton pump in the parietal cells pump hydrogen ions for creation of HCL (requires energy)
4
Q
Chief cells
A
- Secrete pepsinogen which becomes pepsin
- …for the digestion of proteins
5
Q
Mucoid cells
A
- Secrete mucous to protect the lining of stomach from acid
6
Q
The parietal cell is stimulated by three substances
A
- Acetylcholine, histamine, gastrin
- When any one of these substances is released (and receptors are stimulated) it leads to HCL production
- Medications that inhibit HCL secretion work to inhibit these substances or block receptors
7
Q
Control of the GI system: parasympathetic NS
A
- Exerts an excitatory influence to increase digestive secretions and GI muscular activity
- “rest and digest”
8
Q
Control of the GI system: Sympathetic NS
A
- Exerts an inhibitory influence to depress digestive secretions and GI muscular activity
- “FFF”
9
Q
Antacids - Action
A
- Only work on acid already in stomach, not on acid yet to be made
- Repeated doses may be necessary
- May also stimulate mucous production (which is GOOD - mucous protects)
10
Q
Antacids - Effect
A
- Increase the pH of the stomach
- Normal pH of stomach = 1 - 2
- Antacids can change the pH to 3 - 4
11
Q
Antacids - used for ….
A
- peptic ulcers
- heartburn
- gastritis
- gastric hyperactivity - decreases pain associated with it
12
Q
Types of antacids: Aluminum containing
S/E, cautions, Meds
A
- S/E: Constipation
- Caution with Renal failure
- Med: Aluminum hydroxide (Amphogel)
13
Q
Types of antacids: Magnesium containing
S/E, cautions, Meds
A
- S/E: Diarrhea
- Contraindicated with renal failure
- MED: Milk of magnesia (Magnesium hydroxide)
14
Q
Types of antacids: Calcium containing
S/E, med, also produces…
A
- S/E: Kidney stones, constipation, and acid rebound
- MED: Tums
- Also produces gas - often combined with Simethicone (antiflatulent)
15
Q
Types of antacids: Sodium bicarbonate
S/E, Med, mixed
A
- S/E: metabolic alkalosis
- MED: baking soda
- Aluminum and magnesium often mixed (Maalox, Mylanta, etc) - s/e of constipation and diarrhea often balance out. OTC.
16
Q
Types of antacids: Usual dose
A
30 - 60 mL with water every 1 -3 hrs after meals and at HS. Liquid is best, if using tablets, suck until gone. Goal is to coat the stomach.
17
Q
Antacid instructions/warning
A
- Don’t take with other meds - decreases effectiveness of other meds
- Prematurely dissolves enteric coated meds
18
Q
H2 antagonists - actions & details
A
- Inhibits production of HCL
- About 90% effective
- Blocks the histamine 2 receptors on parietal cells
- Makes these cells less responsive to histamine, gastrin, acetylcholine
19
Q
H2 antagonists - uses & S/E & MED
A
- Peptic ulcer disease
- Hyperacidity
- Gastric reflux - Heartburn
- S/E: Very few, very safe, but smoking decreases the action of these medications (available OTC in lower dose)
- MED: Cimetidine (Tagamet). PO, QID, or IV.
20
Q
Other H2 inhibitors & strength compared to Tagamet
A
- Pepcid (famotidine). Very strong, 20 - 50 times the strength of Tagamet.
- Axid (Nizatidine). 4 - 8 times the strength of Tagamet.
- Zantac (Ranitidine). 4 - 8 times the strength of Tagamet.
- All of these can be given BID.
21
Q
Proton pump inhibitors - Actions & details
A
- Newest class of medications for acid disorders
- Inhibits final step in the acid secretion process of the parietal cell
- Binds permanently with H+/K+ ATPase
- stops the supply of energy to the proton pump in parietal cell
- No pumping of H+ = No HCL
- Blocks over 90% of acid production until the parietal cell manufactures new H+/K+ ATPase.
22
Q
Proton pump inhibitors - Uses
A
- Not usually for long-term use
- First line treatment for:
- Erosive esophagitis,
- symptomatic GERD,
- active duodenal ulcers and active benign gastric ulcers, - gastric hypersecretory conditions
- NSAID-induced ulcers and stress ulcer prophylaxis
23
Q
Proton pump inhibitors - S/E & MED
A
- S/E: similar to H2 antagonists - fairly rare
- MED: Omeprazole (Prilosec). PO only - recently OTC with a lower dosage.
- MED: Pantoprazole (Protonix). Given IV, PO, NG (but frequently clogs NG tube - large delayed release granules can’t really be crushed)
24
Q
Acute diarrhea
A
- Sudden onset in healthy person
- Lasts 3 days - 2 weeks
- Causes: Bacterial, Viral, Food poison
25
Chronic diarrhea
- Person has other symptoms such as: Fever, N/V, Wt. loss, loss of appetite, weakness
- Lasts 3 - 4 weeks
- Causes: Bowel disease, Tumors, hyperthyroidism
26
Diarrhea is a symptom not a disease - find the cause!
Need to know the reason for the diarrhea before treatment
27
Antidiarrheal agents - Adsorbents
- Coats walls of GI system
- Binds with bacteria & toxins to eliminate them
- Some have an ASA like substance in them (Bismuth subsalicylate, which can cause dark stool & blue lips)
- MEDS:
1. Kaopectate
2. pepto-bismol
3. Activated charcoal `
28
Antidiarrheal agents - Anticholinergics
- Decreases peristalsis to slow the movement of the GI system
- Serious S/E - prescription only. S/E: HA, N/V, Dry mouth, sweating
MEDS:
1. Donnatal
2. Atropine
29
Antidiarrheal agents - intestinal flora modifiers
- Supplies bacteria to the intestine that will restore the normal flora
- Good for diarrhea associated with antibiotics
- MED: Lactobacillus acidophilus (Bacid)
30
Antidiarrheal agents - Opiates
- Decreases bowel motility
- Eliminates pain
- MEDS:
1. Codeine
2. Diphenoxylate / Atropine (Lomotil)
3. Loperamide (Imodium)
31
Antidiarrheal agents - lil detail
Many medications are combinations of all the antidiarrheals mentioned
32
Laxatives - Use & detail
- For treatment of constipation (infrequent or difficult passage of stool)
- Constipation is also a symptom not a disease - find the cause!
- Usual time from ingestion to defection is 24 - 36 hours
33
Common causes of constipation:
1. Metabolic/endocrine disorders (Diabetes, pregnancy, hypothyroidism)
2. Neurogenic (spinal cord injury)
3. Adverse medication reactions (Analgesics, aluminum antacids)
4. Lifestyle -->
a) poor bowel habits - avoid the urge? no schedule?
b) Diet
c) Activity
d) Psychological - own bathroom? Privacy? etc...
34
Laxatives work by:
1. Changing fecal consistency
2. Increasing movement of GI
3. Removing stool from rectum
There is common misuse of these medications - natural action is better
35
Types of Laxatives - Bulk forming (Actions)
- These add fiber to the intestine
- This fiber pulls water and increases bulk of the stool
- GI reflex moves the stool out because it is so big
36
Types of Laxatives - Bulk forming (NRSG implications & MEDs)
- Often in powder to mix with water
- takes 12 hrs - 3 days to work
- S/E: can dehydrate you
- Best for once in a while use for acute constipation
- MEDS:
1. Metamucil
2. Citrucel
3. Fiberall
37
Types of Laxatives - Emollients, Type #1 = stool softeners
- Works by lowering the tension of fluids so water and fat are pulled into the stool
- Takes 1 - 3 days to work
- Very mild
38
Types of Laxatives - Emollients, Type #2 = Lubricants
- Coats the fecal matter and keeps water from dehydrating stool
- Also makes it slippery
- Takes about 6 - 8 hours to work
- Better for once in a while use
39
Types of Laxatives - Emollients (MEDS)
1. Mineral oil
2. Docusate sodium (Colace)
3. Docusate Calcium (Surfak)
40
Types of Laxatives - Hyper-osmotic Laxatives
- Increases fecal water content
- Causes distention and increased peristalsis
- Works only on the large intestine
- Works very quickly---in hours
- Used for surgical bowel procedures
41
Types of Laxatives - Hyper-osmotic Laxatives (MEDS)
1. Polyethylene glycol (Golytely)
| 2. Lactulose
42
Types of Laxatives - Saline type laxatives
- Inhibits the bowel from taking in water and electrolytes
- Keeps the stool loose and watery
- Increases distention and peristalsis
- Often given in enema
- Enema form takes only 2 - 5 min to work
- Better for chronic constipation
43
Saline type laxatives - MEDS
1. Milk of magnesia
2. Fleet enema
3. Epsom salts
44
Types of Laxatives - stimulant laxatives
- stimulates the nerves of the intestines to increase peristalsis
- Takes 6 - 12 hours to work
- Can be quite harsh
- Better for once in a while use
MEDS:
1. Dulcolax
2. Senokot
45
Considerations of laxative use
1. Take laxatives with plenty of water
2. Long-term use can lead to dependance
3. Don't use with N/V, or abdominal pain
4. No recommended for children
46
Antiemetics (anti-nausea) agents:
Work in two centers in the brain:
1. Vomiting center (VC)
2. Chemoreceptors trigger zone (CTZ) - in brain stem
47
Antiemetics - Anticholinergics
- Action: Binds to and blocks acetylcholine so nauseous stimuli is not sent to brain
- S/E: Drowsiness, Dry secretions, Prevents smooth muscle spasms
- MED: Scopolamine (esp good for motion sickness. Patch behind ear)
48
Antiemetics - Antidopaminergics
- Action: Blocks dopamine receptors in the chemoreceptor trigger zone. Calms the CNS and decreases anxiety and tension.
- S/E: Orth. hypotension, blurred vision, dry mouth, constipation
- MED: Compazine (Rectal, IM, PO)
49
Antiemetics - Prokinetics
- Action: Blocks dopamine in the CTZ. Stimulates acetylcholine receptors in the GI tract.
- S/E: Hypotension, sedation, fatigue, dry mouth, diarrhea
- MED: Metoclopramide (Reglan) ...IV
50
Antiemetics - serotonin blockers
- Action: Blocks serotonin receptors in the GI tract, CTZ, & VC
- Primarily used for chemo-induced N/V
- Also used for some post-op N/V and hyperemesis gravidarium
- Few S/E: Doesn't interact negatively with other medications
- MED: Ondansetron (Zofran) PO & IV. Give before chemo or surgery to prevent N/V
51
Antiemetics - Tetrahydrocannabinoids
- Action: Has an inhibitory effect on the reticular formation, thalamus, and cerebral cortex
- S/E: Drowsiness, dizziness, anxiety, confusion, visual disturbances, dry mouth, increased appetite
- MED: Dronabinol (Marinol) PO
52
Antiemetics - Ginger (Herbal)
- Common uses: sore throat, migraine, HA, N/V, morning sickness, motion sickness
- Adverse effects: Skin reactions, anorexia, N/V
- Med interactions: increased bleeding risks with anticoagulants (warfarin) or antiplatlet medication
53
Enteral feedings
- Feedings through the GI tract
- other: nasogastric, nasoduodenal, nasojejunal, gastrostomy, jejunostomy
- Many commercial formulas made to meet or supplement nutrition.
54
Parenteral feeding
- Feeding directly into Circulatory system by IV
- Also known as total parenteral nutrition or TPN
- Contains vitamins, minerals, amino acids, glucose, etc. Often made by the pharmacy to specifically meet the needs of the patient.
- PIV or central vein
55
Parenteral feeding via PIV
- under 2 weeks of administering
- Supplemental nutrition only
- 500 - 700 calories/day
- S/E: Phlebitis, fluid overload
56
Parenteral feeding via central line
- Long-term administering
- Total nutrition needs met
- 2000 - 4000 calories/day
- S/E: Infection of insertion site at subclavian or jugular vein, hyperglycemia
57
Reasons for Parenteral feeding use:
1. Cancer - radiation/chemotherapy
2. GI illness that prevents oral feeding
3. Extreme surgery
4. Renal failure (reduces toxins)
5. Need for more nutrition than can eat (Burn patient)
