Antimigraine and Antiemetic Drugs Flashcards
What is the pathophys of migraines?
Cerebral vasodilation with activation of pain fibers
MOA of Triptans:
5HT 1B/1D agonists in the vasculature which results in potent vasoconstriction of intracranial blood vessels, inhibition of vasoactive peptides, and interruption of pain signal transmission
Triptans are known as _____ migraine therapy and how are they available?
Specific
SQ, IM, Nasal
Examples of Triptans include:
Sumatriptan (Imitrex) Rizatriptan (Maxalt) Almotriptan (Axert) Frovatriptan (Frova) Eletriptan (Relpax) Zolmitriptan (Zomig) Naratriptan ( Amerge)
Which triptan has the slowest rate of action but also the lowest recurrence rate?
Naratriptan (Amerge)
Which triptan has the fastest onset of action and with what drug should the dose be adjusted?
Rizatriptan (Maxalt)
Propranolol (inhibits the met. of rizatriptan)
In what type of patients are triptans CI in and why?
Ischemic heart disease, uncontrolled HTN, ischemic stroke, pregnancy
They causes potent vasoconstriction
How are most triptans metabolized?
MAO
exceptions eletriptan (CYP3A4), frovatriptin, naratriptan
Which drugs should triptans be avoided in?
MAOI’s (except eletriptan, frovatriptin, and naratriptan
SSRI’s and SNRI’s =increase risk for serotonin syndrome
Two commonly used preparations of Ergots:
Ergotamine
DHE 45
MOA of Ergots:
5HT 1B/1D agonists (potent vasoconstriction of intracranial blood vessels)
Why is Ergotamine not used for the most part?
- Poor bioavail with PO and rectal dosing
- May worsen N/V
- Dose associated vascular occlusion and rebound HA
- Avoid in patients with CAD, PVD, HTN, hepatic or renal disease
Which patients might Ergotamine be most helpful in treating?
Patients with prolonged duration of attacks, >48hrs
DHE45 should be used with an ______ drug. What formulations are they available in?
antiemetic
(overall less SE, no phys. dependence, no rebound headaches)
IM, IV, SubQ, nasal
DHE45 is CI in what type of patients?
HTN, Ischemic heart disease, combo with MAOIs, elderly
Other first line agents for acute migraines include:
High dose NSAIDs
ASA (650-1000mg)
APAP (1000mg)
Combination products (ASA-APAP-caffeine)
What types of drugs can be used as adjunct therapy for the treatment of migraines?
Antiemetics
Benzos
Opioids
Barbiturates
Prevention of migraine and tension HA treatment can include:
Beta-blockers Ca channel blockers TCA's Anticonvulsants (phenytoin, carbamazepine, valproate, gabapentin, topiramate) Ergot derivatives
Which receptors are located in the midbrain involved in emesis?
Dopamine
Muscarinic- cholinergic
Histaminic
5HT3
Which antiemetic agents antagonize dopamine?
Benzamides (metoclopramide-Reglan)
Butyrophenones (Droperidol, haloperido-Haldol)
Phenothiazines (Chlorpromasine, prochlorperazine-Compazine, promethazine-Phenergan)
What antiemetic agents are highly bound to 5HT3 receptors both centrally and peripherally?
5HT3 antagonists
Ondansetron (Zofran), Dolasetron (Anzemet), gransetron (Kytril)
Corticosteroids are used mostly in the prevention of what type of emesis and what is an example of one drug?
Chemo induced N/V
Dexamethasone
Which anticholinergic agents are used to block cholinergic muscarinic receptors and decrease emesis?
Scopolamine
Meclizine
How to antihistamines prevent emesis and what are some examples?
Act directing on the vomiting center and vestibular pathways
Cyclizine, hydroxyzine (Atarax), diphenhydramine (Benadryl)
