Pharmacology Chapter 22
Drugs to cause diarrhea
**page 367
ondansetron (Zofran) 5HT 3 Receptor antagonists
1. Abdominal pain 2. constipation 3. fatigue 4. headache
metoclopramide (Reglan) (4) (dopamine antagonist)
1. Drowsiness 2. fatigue 3. increased depression 4. restlessness
phenothiazines (2 plus 2 drugs)
1. Inhibit vomiting reflex pathways 2.sedating effects help control nausea Drugs: promethazine (Phenergan) prochlorperazine (Compazine)
What to do after administering drugs for constipation?
1. assess abdomen 2. monitor for BM, quality of BM, and side effects
prochlorperazine (compazine) (phenothiazine)
1. blurred vision 2. constipation 3. dizziness 4. dry eyes and mouth 5. muscle spasms 6. jitteriness 7. mouth puckering 8. neutropenia
dopamine antagonists 1 + 1 drug
1. causes food to move more quickly through digestive tract 2. metoclopramide (Reglan)
promethazine (Phenergan) Phenothiazines (8)
1. confusion 2. disorientation 3. dizziness 4. dry mouth 5. n/v 6. rash 7 sedation 8 respiratory depression 9. neutropenia
antihistamines (3) + 2 drugs
1. decrease N/V caused by opiates or motion 2. depress inner ear excitability 3. reducing vestibular stimulation (balance) 4. meclizine (Antivert and Dramamine)
5HT3 receptor antagonist (2 + 1 drug)
1. decrease N/V with chemotherapy 2. block serotonin receptors 3. ondansetron (Zofran)
Anticholinergic Drugs (3) + 1 drug
1. decrease vomiting reflex 2. stops intestinal cramping 3. decreases vestibular input to CNS (Balance) 4. scopolamine (L-hyoscine)
common side effects of antiemetics (11)
1. insomnia 2. diplopia (double vision) 3. tinnitus 4. hypertension 5. photosensitivity 6. EKG 7. tachy/brady 8. urine color changes 9. urinary retention 10. anxiety 11. depression
Constipation (3) characteristics
1. less than three bowel movements a week 2. stools are hard and dry, difficult to eliminate 3. bowel movements can be painful
GI functions (4)
1. taking in fluids and nutrients 2. breaking down food into usable forms 3. absorbing useful nutrients and fluids 4. eliminating waste products
Adverse effects of antiemetics (6)
1.neuroleptic malignant syndrome 2.coma 3.seizures 4.tardive dyskinesia 5.respiratory depression 6.tissue necrosis (IV PUSH undiluted promethazine)
types of antiemetic drugs (5)
1.phenothiazines, 2.anticholinergics 3.antihistamines, 4.5HT3-receptor antagonists and 5.dopamine receptor antagonists
teaching for antiemetics
1don't drive heavy machinery or a car 2change positions slowly 3use sunscreen and wear protective clothing 4educate about NMS and tardive dyskinesia 5Eat fiber and increased fluids to prevent constipation 6 assess for infection (temperature 7. check with dr before taking OTC drugs 8. don't use alcohol or other CNS depressants 9. educate them about urine color changes (prochlorperazine) Compazine 10 use frequent mouth rinses and oral care for dry mouth 11. Do not double dose
Causes of constipation (10)
1low fiber diet 2lack of physical activity 3stress 4pregnancy 5medical diseases 6mental health issues 7decreased fluid intake 8delaying going to the bathroom 9misuse of laxatives 10other drugs affecting nerve activity of colon and fluid balance
Acute diarrhea (3)
3 or more loose stools in 24 hours last <2 weeks Most last <72 hours
what are adverse effects of antidiarrheals?
FiberCon can cause intestinal obstruction Toxic megacolon-Fever, abdominal pain, increased heart rate and dehydration
What to do before administering drugs for constipation?
Look at drugs, including OTC;s ask about bowel habits assess abdomen baseline VS, weight Check BS if diabetic give oral fluid (6 oz) with oral doses Antacids must be one hour apart
Older Adult considerations for constipation
Most drugs are safe for older adults remind them to follow directions encourage them to increase fluid intake
Adverse reactions
RARE=allergic reactions
bulk forming laxatives (Metamucil)(2)
add bulk to stool Can be used long term (more than one week)
Emmolient/Stool softeners (Colace)
allow stool to mix with fatty substances
Three types of antidiarrheal drugs
antimotility adsorbent/absorbent antisecretory
ped considerations for antiemetics
assess for muscle spasms watch for balance disturbance (used for cancer chemo) teach parents to read drug label
pregnancy considerations for antiemetics
avoid when breastfeeding
Why don't we want to give drugs for an infection from bacteria or parasites
can make the condition worse
osmotic laxatives (fleet's) (MOM) GoLYTELY Mirilax (Saline)
cause retention of fluid in the bowel Can cause electrolyte imbalances when used too often
interventions before giving antiemetics
causes of N/V history of depression (reglan) dilute for IV Push
interventions after giving antiemetics
check LOC check sedation (particularly with older adults assess N/V if they cause GI symptoms for the patient, give them with food milk or a full glad of water
lubricants (to treat constipation) glycerin or castor oil + (five adverse events
coat surface of stool and help hold water ADVERSE EVENTS 1confusion,2 irreg heartbeat, 3cramps, 4rash, and 5unusual weakness or tiredness
antimotility drugs
decrease peristalsis
how do antisecretory drugs work?
decrease secretion of intestinal fluids and slow bacterial activity
antisecretory drugs (2)
decrease secretions in the GI tract and treat diarrhea
Motility disorder 1 + 2 examples
decreased contact time IBS diabetic neuropathy
Exudative 2 charact. + example
defective colonic absorption outpouring of mucus/blood Crohn's
side effects of drug therapy for constipation (8)
diarrhea skin rash stomach cramps abdominal distention nausea gas reflux headache
consult doctor for constipation when 4
doens't respond to treatment symptoms are severe last more three weeks or complications occur (bleeding) **Rule out colon cancer**
What should be taught when giving drugs for constipation (6)
drink 1500-2000 mL of fluid take with several oz of fluid 6-8 they should only be used short term space antacids from these meds (space at least one hour) call dr if constipation is not relieved, signs of fluid imbalance, or rectal bleeding
meclizine (Antivert) side effect (antihistamine)
drowsiness
stimulant laxatives (Dulcolax) + adverse reaction
increase peristalsis May cause hypokalemia ADVERSE-dysrhythmias
secretory diarrhea 1 + 2 examples
increased secretion of electrolytes Ecoli ileal resection (surgery)
Older adult considerations for antiemetics
increased side effects of confusion and dizziness, shaky hands, and balance disturbance, and heat-related disorders May need lower dose
diarrhea (3)
is a symptom can cause dehydration can cause electrolyte imbalance
Chronic diarrhea (3)
lasts longer than two weeks may not have a stool every day most common cause is enteritis
What to do before giving antidiarrheals?(4)
list of drugs (including otc) weight and VS Check for dehydration listen to abdomen
Types of diarrhea 4
osmotic secretory exudative motility disorder
What to do after giving antidiarrheals
reassess watch for signs of megacolon monitor for change in VS,
absorbent drugs
remove substances that cause diarrhea
how do adsorbent/absorbent drugs work
remove substances that cause diarrhea from teh body
Pregnancy considerations for constipation
safe to use during pregnancy fleets should not be used
How do antimotility drugs work?
slow the movement of stool through the bowel, allowing for more time for water and salt to be absorbed
Intended responses for drug therapy for constipation
soften, pass stool relieve or prevent constipation
osmotic diarrhea 1 + 2 examples
unabsorbed solutes lactose deficiency mg excess
what are side effects of antidiarrheals?2
uncommon for healthy adults constipation
When would drugs for constipation be contraindicated
undiagnosed abdominal pain r/t risk of increased peristalsis and risk of bowel perforation
Pediatric considerations for constipation
usually 1/2 the dose of adults follow specific instructions from the prescriber
What do we need to educate clients with diabetes about using bulk forming drugs?
watch for those that contain sugar