Lecture 4 (Antiemetic and Antianginal Drugs) Flashcards
what is emesis?
- forcible emptying of gastric acid and stomach contents
- occasionally intestinal contents as well
what are antiemetic drugs used for?
used to relieve nausea and vomiting
what stimulates vomiting?
- Vomiting center (VC)
- chemoreceptor trigger zone (CTZ)
both located in the brain, when stimulated cause vomiting reflex
what are the different types of nausea and vomiting?
1) chemotherapy induced
2) post operative
3) general
describe the signal pathways that cause nausea and vomiting(3)
1) the gastrointestinal tract, labyrinth (inner ear), and cerebral cortex sends signals to the chemoreceptor trigger zone (CTZ)
2) the chemoreceptor trigger zone (CTZ) sends a signal to the vomiting center in the medulla
3) the vomiting center in the medulla initiates the vomiting reflex
what is the mechanisms of action of antiemetics?
antiemetics work by blocking one of the vomiting pathways which blocks the stimulus that induces vomiting
what is the general use for each type of antiemetic?
the prevention and reduction of nausea and vomiting
what are two antiemetics?
1) prokinetic metoclopramide (Reglan)
2) serotonin blockers ondansetron (Zofran)
what is the mechanism of action for metaclopramide (Reglan)?
- blocks dopamine receptors in the CTZ
- causes CTZ to be desensitized to impulses it receives from the GI tract
what does metaclopramide (Reglan) do to peristalsis?
it stimulates peristalsis in the GI tract which enhances emptying of stomach contents
what is metaclopramide (Reglan) and what is it used for?
it is an antiemetic used to treat nausea and vomiting, but it is also used for:
* gastroesophageal reflux disease
* delayed gastric emptying
what are the adverse effects related to metaclopramide (Reglan)(9)?
1) hypotension
2) supraventricular tachycardia
3) sedation
4) fatigue
5) restlessness
6) dry mouth
7) nausea & vomiting
8) diarrhea
9) irreversible tardive dyskinesia (if used long-term)
what is tardive dyskinesia?
chronic condition that causes involuntary repetitive face and jaw movements
what is ondansetron (Zofran) and what is it used for?
it is an antiemetic that is used for nausea and vomiting in:
* patients receiving chemotherapy
* post operative patients
what is the mechanism of action of ondansetron (Zofran)?
blocks serotonin receptors in the GI tract, CTZ, and VC
what are the adverse effects associated with ondansetron (Zofran)(4)?
1) headache
2) diarrhea
3) rash
4) bronchospasm
why do you need to warn patients about driving or performing hazardous work while on antiemetics?
they can cause severe drowsiness
why should patients on antiemetics avoid alcohol?
when taken together they can cause severe central nervous system depression
why should you teach patients on antiemetics to change positions slowly?
to avoid hypotensive effects
for chemotherapy, antiemetics are given when?
30 - 60 minutes before chemotherapy
what is angina pectoris?
chest pain
what issues with the heart causes angina pectoris?
when the supply of O2 and nutrients in the blood is insufficient to meet the demands of the heart, the heart muscle aches
what is ischemia?
poor blood supply to an organ
what causes ischemic heart disease?
1) poor blood supply to the heart
2) Atherosclerosis
3) Coronary artery disease
what does MI do to the tissue of the heart?
causes necrosis of the cardiac tissue
how does a heart attack occur?
occurs when a portion of the heart is deprived of oxygen due to blockage of a coronary artery
describe the different types of angina
1) chronic stable angina: triggered by physical exercise or stress
2) unstable angina: pre-infarction- chest pain 24 hours before a MI
3) vasospastic angina: recurring episodes of chest pain at rest and at bedtime from midnight to 0800; can be expressed at chest discomfort or pain to neck, jaw, shoulder, or arm
what are/is nitrates; nitroglycerine?
rapid acting forms
1) used to treat acute angina attacks
2) available in sublingual and IV infusion
nitroglycerine (both rapid and long-acting)
1) prototypical nitrate
2) large first-pass effect with oral forms
3) used for symptomatic treatment of ischemic heart conditions (angina)
apart from angina, what else is nitroglycerine used for?
IV form used for:
* BP control in perioperative hypertension
* treatment of heart failure
* ischemic pain
* pulmonary edema associated with acute MI
* hypertensive emergencies
what is the mechanism of action of nitrates?
1) causes vasodilation by relaxing smooth muscles of the blood vessels (including coronary arteries).
2) allows O2 to get to ischemic myocardial tissue
used for prevention and treatment of angina
what are the therapeutic effects associated with nitrates?
1) minimize the frequency of attacks and decrease the duration and intensity of anginal pain
2) improve the patient’s functional capacity with as few adverse effects as possible
3) prevent or delay the worst possible outcome (MI)
what are the adverse effects associated with nitrates(4)?
1) headaches (usually get less severe with frequent use)
2) reflex tachycardia
3) postural hypotension
4) tolerance may develop
what are the contraindications associated with nitrates(5)?
1) known drug allergy
2) severe anemia
3) closed-angle glaucoma
4) severe head injury
5) use of ED drugs sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra)
what is the most important drug used in the treatment of ischemic heart conditions such as angina?
nitroglycerin
drug dosage information for nitroglycerin
* routes
* onset of action
* peak
* elimination half-life
* duration of action
- routes: PO, SL, metered-dose aerosol (sprayed under tongue), IV, and topical
- dosage: SL-0.4 mg or 1-2 sprays oral
- onset of action: 2-3 minutes
- peak: unknown
- elimination half-life: 1-4 minutes
- duration of action: 0.5-1 hour
what do you need to obtain before giving nitroglycerin?
- baseline vitals including respiratory patterns and rate
- assess for drug interactions
what should patients be encouraged to limit while taking nitroglycerin?
caffeine intake
what are some things patients should report while taking nitroglycerin(8)?
1) blurred vision
2) persistent headache
3) dry mouth
4) edema
5) fainting episodes
6) weight gain of 2 lbs. in one day or 5 lbs. in one week
7) pulse of less than 60 bpm
8) dyspnea
what are some things that can increase the risk of fainting while on nitroglycerin? why?
1) alcohol consumption
2) spending time in hot tubs, hot baths, or saunas
these cause vasodilation. paired with nitroglycerin, they can cause fainting
patients on nitroglycerin should be encouraged to keep a record of anginal attacks. what should be included in that record?
1) precipitating factors
2) number of pills taken
3) therapeutic effects of the medication (how well did they help?)
what does a burning sensation in the mouth with SL nitroglycerin indicate?
that the drug is still potent
how long is SL nitroglycerin good for?
about 3 months after opening; patients should keep a fresh bottle on them at all times
how do you preserve the potency of nitroglycerin?
store in an airtight dark glass bottle with a metal cap and no cotton filler
what should patients take nitroglycerin?
NPO at the first hint of anginal pain
when do you monitor vital signs in patient with angina?
during acute exacerbations of angina and during IV administration of nitroglycerin
if a patient is experiencing anginal pain and needs to take nitroglycerin, what should they do?
lie down to prevent or decrease dizziness and fainting that may occur due to nitroglycerin related hypotension
if anginal pain occurs, what should people do(3)?
1) stop activity, sit or lie down, and take a SL nitroglycerin tablet
2) if there is no relief in 5 minutes, call 911 and take a second tablet
3) if there is no relief in 5 minutes take a third tablet
DO NOT TRY TO DRIVE TO THE HOSPITAL
