Pharmacology of Nausea and Vomiting Flashcards
the tendency to vomit or as a feeling in the throat of epigastric region alerting an individual that vomiting is imminent
nausea.
the ejection or expulsion of gastric contents through the mouth. often requiring a forceful event.
vomiting.
list the 10 common causes of nausea?
1- chemotherapy.
2- general anesthesia.
3- viral gastroenteritis.
4- gastroparesis.
5- migraine.
6- motion sickness.
7- overdose of alcohol.
8- vertigo.
9- rotavirus.
10- pregnancy.
VOMIT stands for?
V- Vestibular.
O- Obstruction or drugs like Opiates.
M- Mind (dysmotility).
I- Infection (irritation of gut).
T- Toxins (taste and other senses).
list agonists and antagonists of antiemetics?
Antagonist: 5-HT3 RAs
agonist: 5-HT3.
antagonist: promethazine.
agonist: H1.
antagonist: atropine.
agonist: M.
antagonist: domperidol.
agonist: D2.
antagonist: NK1-RA
agonist: Substance P.
common condition of nausea and vomiting are?
1- motion sickness.
2- pregnancy.
3- hepatitis.
chemotherapeutic agents can directly activate what?
CTV or vomiting center.
chemotherapeutic agents can also act peripherally by what?
causing cell damage in the gastrointestinal tract and releasing serotonin from the enterochromaffin cells of the small intestinal mucosa serotonin activates 5-HT3 receptors.
uncontrolled vomiting can produce what?
1- dehydration.
2- metabolic imbalances.
3- nutrient depletion.
give example of a drug effective in motion sickness that works as a M1 receptor antagonists?
hyoscine (scopolamine) (transdermal scop).
give examples of a drug effective in motion sickness that works as a H1 receptor antagonists?
1- dimenhydrinate (dramamine).
2- diphenhydramine (dramenex).
3- cyclizine (emetrex).
4- meclizine (navidoxine).
list the properties of H1 and M1 receptor antagonists?
- very useful in motion sickness.
- ineffective against substances that act directly on the CTZ.
- they don’t work once vomiting has started.
list drugs that are D2 receptor blocker?
1- phenothiazine compounds: prochlorperazine (emadrotec).
2- substituted benzamides: metoclopramide (primperan).
3- butyrophenones: droperidol (inapsine), haloperidol (haldol).
4- domperidone (motilime).
what is the first group of drugs shown to be effective antiemetic agents?
phenothiazine compounds.
what are the side effects of prochlorperazine?
1- hypotension, restlessness, extrapyramidal symptoms and sedation.
2- effective against moderately emetogenic chemotherapeutic agents.
which drug prevents emesis in 30-40% and reducing emesis in the majority?
metoclopramide (primperan)
what are the side effects of metoclopramide (primperan)?
- anti-dopaminergic side effects, including sedation, diarrhea and extrapyramidal symptoms, limit its high dose use.
what are the uses of Doperidol (inapsine) and Haloperidol (haldol)?
- moderately active anti-emetics.
- high doses of haloperidol effective in preventing cisplatin (anticancer drugs) induced emesis).
what are the uses of Domperidone (motilime)?
- nausea and vomiting (block D2 receptors are found in CTZ).
- restore motility and tone to the upper GIT and facilitate gastric emptying regulates and duodenal function.
what are the side effects of Domperidone (motilime)?
- anti-dopaminergic side effect and increase level of prolactin hormone.
list drugs that are 5-HT3 receptor blockers?
1- ondansetron (zofran).
2- granisetron (kytril).
3- tropisetron (navoban).
4- dolasetron (anzemet).
5- palonosetron (aloxi).
how do we administer 5-HT3 receptor blockers?
IV and orally.
what are the uses of 5-HT3 receptor blockers?
- prevention of nausea and vomiting associated with surgery and cancer chemotherapy.
what are the side effects of 5-HT3 receptor blockers?
headache and diarrhea.
benzodiazepine target which receptor?
GABA A
give examples of benzodiazepine that can be used as antiemtics?
1- lorazepam (ativan).
2- alprazolam (xanax).
list the properties of benzodiazepines?
- their antiemetic potency is low (not useful).
- their beneficial effects may be due to their sedative and anxiolytic properties.
- useful in treating anticipatory vomiting.
give examples of corticosteroids that can be used as antiemetics?
1- methyl-prednisolone (depo-medrol).
2- dexamethasone (epidron).
corticosteroids are effective against what?
moderately emetogenic chemotherapy.
what is corticosteroids mechanism of action?
not known, may involve blockade of prostaglandins.
give examples of cannabinoids used as antiemtics?
1- dronabinol.
2- nabilone.
cannabinoids are effective against?
moderately emetogenic chemotherapy.
why aren’t cannabinoids used?
due to serious side effects, including:
1- hallucinations.
2- sedation.
3- vertigo.
4- disorientation.
give an example of NK1 receptor blocker?
aprepitant (depo-medrol).
NK1 receptor blocker is a new class of drugs called?
substance P antagonists (SPA).
NK1 receptor blockers mediates its effect by?
blocking the neurokinin 1 (NK1) receptor.
aprepitant is metabolized primarily by what?
CYP3A4
aprepitant can affect the metabolism of what?
other drugs such as warfarin.
what are the side effects of NK1 receptor blocker?
constipation and fatigue.
antiemetic drugs are often combined to?
increase antiemetic activity or decrease toxicity.
dexamethasone increase antiemetic activity when given what what?
metoclopramide or a 5-HT3 antagonist.
diphenhydramine is combine with?
metoclopramide to reduce extrapyramidal side effects.
what is the first line therapy for morning sickness during pregnancy?
pyridoxine (vit B6)
what to give to pregnant women for morning sickness is symptoms persist (after pyridoxine)?
addition of antihistaminic such as meclizine.
(meclizine + pyridoxine)
what antiemetics are used in children?
corticoadrenal extract + pyridoxine
what antiemetics come from natural sources?
ginger extract for prophylaxis of motion sickness.
