Drugs- Migraine/Headaches (Kinder) Flashcards
Migraine headache
Unilateral in 60-70%;
bifrontal or global in 30%
Gradual in onset, crescendo pattern; pulsating; moderate or severe intensity; aggravated by routine physical activity
Patient prefers to rest in a dark, quiet room, more commonly women
lasts 4-72 hours
Nausea, vomiting, photophobia, phonophobia; may have aura
tension headache
MC type of headache
Bilateral, head band configuration
Pressure or tightness which waxes and wanes
“hat band pattern)
Patient remains active or rests
Variable duration
No associated symptoms usually
cluster headache
Always unilateral, usually begins around the eye or temple
Pain begins quickly, reaches a crescendo within minutes; pain is deep, continuous, excruciating, and explosive in quality
Patient remains active
30-180 minutes duration
Ipsilateral lacrimation and redness of the eye; stuffy nose; rhinorrhea; pallor; sweating
what is the pathophysiology of migraines?
(1) Involves the trigeminal nerve distribution to intracranial and possibly extracranial arteries.
(2) These nerves release peptide neurotransmitters, especially calcitonin gene-related peptide (CGRP), an extremely powerful vasodilator, as well as substance P and neurokinin A.
(3) Along with promoting vasodilation, these peptide neurotransmitters lead to dural plasma extravasation resulting in neurogenic inflammation.
(4) Mechanical stretching caused by perivascular edema may be immediate cause of activation of pain nerve endings in the dura.
what are common triggers for migraine
(1) Food: alcohol, caffeine/caffeine withdrawal, chocolate, monosodium glutamate, aspartame.
(2) Environment: flickering lights, high altitude, strong smells/fumes, tobacco smoke, weather.
(3) Behavioral: excess/insufficient sleep, fatigue, menstruation, skipped meals, strenuous activity, stress.
where is serotonin found in the body
iii) Over 90% of serotonin in body found in enterochromaffin cells in the GI tract.
iv) In blood, serotonin found in platelets. Concentrated via an active serotonin transport mechanism (SERT) similar to that in membrane of serotonergic nerve endings.
what is monoamine oxidase’s effect on serotonin
v) Monoamine oxidase (MAO) oxidizes/inactivates serotonin. Immediate product of metabolism, 5-hydroxyindoleacetaldehyde, further oxidized to 5-hydroxyindoleacetic acid (5-HIAA).
5-HIAA may serve as a measure of serotonin synthesis; 24 hour excretion used as a diagnostic test for tumors synthesizing excessive quantities of serotonin (carcinoid tumor).
why is serotonin important in migraines
b/c its actions are involved in the perception of pain
what are the effects of serotonin in the heart
ii) CV: contraction of vascular smooth muscle (5-HT2), vasoconstrictor except skeletal muscle and heart where it causes dilation of blood vessels, venoconstriction, small direct positive chromotropic and inotropic effects on heart, promotes platelet aggregation (activation of 5-HT2 receptors).
GI effects of serotonin
iii) GI: increases tone and peristalsis (5-HT2), motility enhancing or “prokinetic” effect (5-HT4).
what are the effects of serotonin on skeletal muscle and what is serotonin syndrome
iv) Skeletal muscle: serotonin syndrome associated with skeletal muscle contraction (precipitated when MAO inhibitors given with serotonin agonists, especially antidepressants such as selective-serotonin reuptake inhibitors, SSRIs).
the “Triptan” drugs used in migraine are working at what receptor by what mechanism of action
b) MOA: activates 5-HT1D/1B receptors on presynaptic trigeminal nerve endings inhibiting release of vasodilating peptides;
stimulates vasoconstriction preventing vasodilation/stretching of pain endings.
MOA of triptans
b) MOA: activates 5-HT1D/1B receptors on presynaptic trigeminal nerve endings inhibiting release of vasodilating peptides; stimulates vasoconstriction preventing vasodilation/stretching of pain endings.
serotonin AGONISTS
what is the prototype triptan
sumatriptan
which triptans are metabolized by MAO-A and why is this clinically significant
sumatriptan, zolmitriptan, and rizatriptan
do NOT take these drugs if also on a MOA inhibitor
which triptans are metabolized by CYP450
eletriptan, naratriptan, and frovatriptan
which triptan is metabolized by both MAO-A and CYP450
almotriptan
what is the therapeutic use of triptans
d) Therapeutic use: currently 1st line for acute mild-to-severe migraine attacks in most patients. Also used as rescue therapy when nonspecific medications ineffective.
in what pt’s are triptans contraindicated
coronary artery disease, angina, ischemic heart disease, uncontrolled hypertension.
do NOT use within 24 hours of ergotamine derivative
what are some ADR’s of triptans
chest pain- due to coronary spasm (1-5 % of pt’s)
e) ADRs: most are mild – altered sensations (tingling, warmth), dizziness, muscle weakness, fatigue, flushing, drowsiness, nausea, sweating, neck pain.
injectable sumatriptan can cause injection site reaction
dihydroergotamine (DHE)
ergot alkaloid