Chapter 50
Acid-Controlling Drugs
Acid-Controlling Drugs
What do antacids do?
Neutralize stomach acid secretion
What are the different categories of antidiarrheals?
- adsorbents (i.e., bismuth subsalicylate)
- antimotility drugs (anticholinergics and opiates)
- probiotics
Name an anticholinergic drug used to treat nausea.
scopolamine
What are the different types of antacids (they can be used alone or in combination)?
- Aluminum salts
- Magnesium salts
- Calcium salts
- Sodium bicarbonate
What is bismuth subsalicylate indicated for and what is its MOA?
- antidiarrheal (it is an adsorbent)
- coats the walls of the GI tract; binds to causative bacteria or toxin, which is then eliminated through the stool
Name a serotonin blocker that is used to treat nausea and vomiting.
ondansetron
What is important to remember with each of these types of antacids?
1. Calcium
2. Magnesium
3. Sodium bicarbonate
1. Calcium antacids may lead to the development of kidney stones.
2. Magnesium antacids must be avoided in patients with renal failure.
**(Excretion is affected with renal failure. Magnesium is important for heart function -- too much magnesium can be dangerous for the heart).
3. Sodium bicarbonate has a quick onset but short duration of action.
What is often given to patients who are experiencing diarrhea while completing a course of antibiotic therapy?
A probiotic (i.e., Lactobacillus acidophilus)
What are some adverse effects associated with scopolamine?
- dizziness, drowsiness, disorientation
- difficult urination (urinary retention -- remember, it is an anticholinergic)
- blurred vision, dry mouth (again, it is an anticholinergic)
What are some contraindications to taking antacids?
- Severe renal failure or electrolyte disturbances
**These conditions can cause a toxic accumulation of the electrolytes in the antacids.
- GI obstruction
**Antacids can stimulate GI motility. If the patient has a GI obstruction, increased motility of the GI tract would not be desired.
What are some adverse effects associated with adsorbents such as bismuth subsalicylate?
- dark stools
- metallic taste
- increased bleeding time (when given with anticoagulants such as warfarin)
**FYI: Adsorbents bind to vitamin K, which is needed to make certain clotting factors. Vitamin K is synthesized by the normal bacterial flora in the bowel.
1. Name a prokinetic drug used to treat nausea and vomiting.
2. What other conditions does this drug treat?
1. metoclopramide
2. GERD and delayed gastric emptying
Which of the antacids is often recommended for patients with renal disease?
Aluminum salts (it is excreted more easily)
What are the adverse effects associated with anticholinergics?
"Can't see, can't pee, can't spit, can't sh_t"
What are some adverse effects associated with serotonin blockers (i.e., ondansetron)?
- headache
- prolonged QT interval
What is an adverse effect of overusing an antacid?
Metabolic alkalosis (remember, these drugs neutralize acid in the stomach -- the cause is not respiratory = metabolic, less acid = alkalosis)
What is lactulose given for?
- laxative (treats constipation)
- also used to reduce elevated serum ammonia levels (i.e., as seen with liver cirrhosis)
What are the nursing implications with antiemetics?
- Taking antiemetics with alcohol may cause severe CNS depression.
- Patients should change positions slowly to avoid hypotensive effects.
What adverse effect is associated with both aluminum salts and calcium salts?
constipation
What is important for the nurse to do before starting therapy with a laxative?
Assess the patient's fluid and electrolytes (all laxatives can cause electrolyte imbalances!)
Which of the antacids has the adverse effect of diarrhea?
Magnesium salts
When should a patient not take a laxative?
If they are experiencing nausea, vomiting, or abdominal pain (symptoms could indicate a possible intestinal obstruction).
What is the MOA of histamine 2 (H2) receptor antagonists?
They reduce acid secretion, thereby helping relieve heartburn (GERD).
What should the nurse teach a patient taking bulk-forming laxatives (such as psyllium)?
Take bulk-forming laxatives with at least 240 mL (8 oz) of water.
Name one drug that is an H2 antagonist.
famotidine
Why can the long-term use of laxatives be a problem?
They can decrease bowel tone and may lead to dependency.
If taking both a H2 receptor antagonist and an antacid for GERD, when should each be taken?
H2 receptor antagonists should be taken 1 to 2 hours before antacids.
Name a drug that is a proton pump inhibitor.
omeprazole
What are some adverse effects of proton pump inhibitors?
- osteoporosis and risk of fractures in long-term users
- depletion of magnesium