Pharm 3: Flashcards
1
Q
Nausea
A
- unpleasant feeling
- Decreased Gastric Motility
- Increased Intestinal Tone
2
Q
Retching
A
- Spasmodic respiratory contractions
- closed glottis
3
Q
Emesis means
A
Vomiting
4
Q
Vomiting Results when
A
- Deep breath
- Larynx raised to open esophageal sphincter
- soft palate raise to close nares
- Diaphragm contracts down
- negative thorax pressure
- facilitates esophagus opening
- Abdominal muscles contract expelling stomach contents
- w/pyloris closed only way is out
Controlled by THE CNS
5
Q
Emesis Center
A
- aka Vomiting Center
- Medullary
- receives afferent input from periphery
- pharyxn
6
Q
Chemoreceptor Trigger zone (CTZ)
A
- in area postrema
- projects to Emesis center
7
Q
Afferent input to EC
A
- CTZ
- GI Tract
- vagal and sympathetic
- mucosal irritatioin
- GI distention
- Non-GI visceral input
- bile ducts
- peritoneum
- heart
- Vestibular system
- Forebrain input
- psychological factors
8
Q
Emesis: Treatment
A
- Depends on etiology
- peripheral
- inflammation
- toxins
- CTX and other drugs
- motion sickness
- Psychological factors
- peripheral
9
Q
Classes of Antiemetic Drugs
A
- 5-HT3 antagonists
- NK1 (Neurokinin 1) receptor antagonist (anti-substance P)
- Phenothiazines and butyrophenones
- anti-dopaminergic antipsychotics
- Substituted benamides
- anti-dopainergic
- Benzodiazepines
- effective against psychologically-induced emesis
- H1 antagonists
- anti-cholinergics
- Cannabinoids
- Corticosteroids
10
Q
5-HT3 Antagonists
A
- Receptors present on visceral afferents in CZ and EC
- GOOD TARGET
- Setron Family
- Graniseetron
- Dolasetron
- Ondansetron (zofran)
- Good efficacy against chemotherapy-induced N&V (CINV)
- interfere w/vagal afferents
- less effective against motion sickness and psychologicall-induced emesis
- Long Half-lives
- QD or BID dosing
- Extensive Liver metabolism
- Hepatic impairment=dose reduction
- Good toxicity profile
- headache, dizziness, constipation
- some prolonged QT
- Dolasetron
11
Q
NK1 Antagonists
A
- AKA substace P and Tachykiniin receptor antagonists
- Receptors present in GI, CTZ and NTS (Vomitng center)
- GOOD TARGET
- -Pitant
- Aprepitant (FDA Approved)
- Fosaprepitant (IV aprepitant)
- Rolapitant (FDA approved)
- Casopitant (Close to EU approval)
- Vestipitant (In clinical Trials)
- Long duration of action
- More effective than 5HT3 antagonists against the second phase of CINV
- Evidence:
- anxiolytic and antidepressant
- Problems:well tolerated
- decreased appetite
- dizziness
- indigestion
12
Q
Phenothiazines
A
- Antagonist of dopamine receptors
- especiallly in CTZ
- good antihistamines also
- Phenothiazines
- Prochlorperazine
- Promethazine
- Thiethylperazine
- Butyrophenone
- Droperidol
- Black box warning due to prolonged QT
- only at high antipsychotic dose
- effective against post-op N&V (PONV)
- Adverse Effects:
- Extrapyramidal
- tardive dyskinesia
- Prolonged QT, Torsades w/droperidol
- Extrapyramidal
13
Q
Substituted Benzamides
A
- Metoclopramide and trimethobenzamide
- dopamine receptor antagonists
- (other effects also)
- Mechanism unclear
- dopamine receptor antagonists
- Adverse events:
- Extrapyramidal
- tardive dyskinesia
- treatment sould be short term
- Class action law suits-patients tx longer than 12 weeks
- tardive dyskinesia
- Extrapyramidal
14
Q
H1 Antihisatmines
A
- first generaiton antihistamines
- Diphenhydramine and Dimenhydrinate
- Effective against motion sickness
- Problems: Sedation and Anticholinergic effects
- or a benefit
- Newer generation
- Meclizine
- Fewer Anticholinergic effects
15
Q
Scopolamine
A
- Muscarinic Antagonist
- very effect against motion sickness
- Problems: anticholinergic effects
- Transdermal patch localizes effects
- to some extent
