45b - Vertigo Therapy Flashcards
Which drugs produce notable irreversible ototoxicity?
aminoglycoside antibiotics and cisplatin, also possibly loop diuretics
What drugs can cause ototoxicity?
aminoglycosides, erythromycin, minocycline, fluoroquinolones, NSAIDs/salicylates, loop iduretics, cytostatic drugs and antimalarials
How do aminoglycosides cause ototoxicty?
drug entry into the outer hair cell results in cell death by either caspase-dependent OR independent mechanisms.
1 AG entry into outer hair cell through mechnoelectrical channels
2 formation of AG-iron complex creacts with arachidonic cid to form ROS
3 ROS can activate JNK
4 JNK translocates to nucleus to activate cell death
How does cisplatin cause hair cell death?
through caspase dependent mechanisms.
- CP enters outer hair cell
- CP forms mnohydrate complex MHC, MHC activates NOX-3, resulitng in ROS
- ROS activates JNK which translocates to nucleus
- nuclesu activates genes in cell death pathway to translocate to mitochondria
- mitochondria releases cty c and triggers Capsase apoptosis
How do loop diuretics cause ototoxicity?
by their natural mechanism of inhibiting Na/K/2Cl co-transporter, which is important in the ears as well as kidneys. Act through the stria medullaris to cause edema and loss of function that is dose-dependent.
What are treatments for vertigo?
M1 or H1 antagonists OR diazepam for psychosomatic induced vertigo
BBW for promethazine?
BBW for use by injection. Sedation and fatal respiratory depression
What are ADE of scopalamine?
xerostomia, drowsiness, oular effects after touching patch.
What is longest acting anti-vertigo drug?
scopalamine transdermal patch
What is MOA of meclinzine?
H1 and M1 antagonist
What is MOA of promethazine?
H1 and M1 antagonist
What is MOA diphenhydramine?
H1 and M1 antagonist
Which anti-vertigo drug should NOT be used with a cyp2D6 inhibitor?
meclizine because it is predominantly hepatic CYP2D6 metabolized.
Which antiemetic needs dose adjustmant in hepatic dysfunction?
ondansetron
ADE of D2 receptor antagonists?
chronic use leads to bone marrow suppression and blood dyscrasias,
risk of proonged QT and torsade de pointes
Don’t give with antipsychotics
Where do NK1 antagonists act?
in the substantia nigra
What is primary interaction concern with N1 antagonists?
they are CYP3A4 inhibitors.
What is mechanism of cannabinoid agonists?
G-protein coupled decrease in neuronal activity in medullary vomiting center and solitary tract nucleus.
ADE of cannabinoid receptor agonists?
causes high. Caution in pts with history of stustance abuse. Most ommon effect is elation and heightened awareness
What is treatment of choice for emesis from antineoplastics?
serotonin receptor antagonist + a corticosteroid and possibly an NK-1 antagonist.
What is mechanism of corticosteroids as anti-emetics?
act on steroid receptors in STN to possibly reduce release of serotonin.
