Nausea and vomiting Flashcards
Chemical transmitters involved in vomiting
Dopamine: D2 receptors
ACh: MR in vomiting center
Histamine: H1 receptors
Serotonin: 5HT3 receptors
Indications of H1 R antagonists
N&V induced by any stimuli.
Vomiting produced by substance acting directly on CTZ
Motion sickness, substances acting on stomach
H1 R antagonist drugs are
Cyclizine
Cinnarizine
Buclizine
Doxylamine
Promethazine
Sedation in H1 R antagonist
Promethazine and Doxylamine
Cyclizine
Cinnarizine
MOA of Cyclizine
inhibits H1 R in VC
also has antimuscarinic activity
I of Cyclizine
for all types of vomiting including motion sickness
DOA of cyclizine
4-6 hrs
AE of Cyclizine
Drowsiness
Xerostomia
CI of Cyclizine
Closed angle Glaucoma
Urinary retention
Prostatic hypertrophy
Chronic pulmonary disease
acute asthma
DI of Cyclizine
CNS depressants
Anti-cholinergics: incr. their effects
MOA of Cinnarizine
inhibits H1 R in VC and vestibular system
also has antimuscarinic activity
I of Cinnarizine
motion sickness
Vestibular disorders (meniere’s)
Half-life of Cinnarizine
3-6 hrs
AE of Cinnarizine
Extrapyramidal symptoms
Depressive feeling (with prolonged therapy)
Hypotension (high doses)
CI of Cinnarizine
Hypersenstivity to drug
DI of Cinnarizine
CNS depressants
Anti cholinergics
Anti histamines
MAOi
TC antidepressants
MOA of Doxylamine
competes for H1 R sites on target cells
has anti-cholinergic effects= depresses labyrinthine function, blocks CTZ, diminishes vestibular stimulation
Doxyalmine can be used
alone or with Pyridoxine and dicyclomine
Half-life of doxylamine
10-12 hrs
AE of Doxylamine
Tachycardia
urinary retention
constipation
drowsiness
blurred vision
CI of doxylamine
children <12 years
DI of doxylamine
CNS depressants
Anti-cholinergics= incr. their effects
MOA of Buclizine
inhibits H1 R in VC and vestibular system
also has anti-cholinergic properties
I of Buclizine
Motion sicness
radio/chemo induced NV
AE of Buclizine
sedation
dizziness
headache
anxiety
hypotension
dry mouth-xerostomia
tight chest
urinary retention
CI of Buclizine
Asthma
Pulmonary disease
bladder neck obstruction
Closed angle Glaucoma
DI of Buclizine
CNS depressants
MOA of Promethazine HCL
inhibits D2 R, MR and H1 R
crosses BBB
I of Promethazine HCL
all types of vomiting including:
severe morning sickness (only if essential)
Prevention of motion sickness
HAlf-life of Promethazine HCL
10-14hrs
AE of Promethazine HCL
strong sedative effect
dizziness
fatigue
incoordination
Extrapyramidal symptoms
CI of Promethazine HCL
children <2years
DI of Promethzine HCL
CNS depressants
ANti-cholinergic agents