Migraine Pharmacology Flashcards
Triptans
Triptans are a family of tryptamine-based drugs used as abortive medications in the treatment of migraines.
Selective agonist effects on serotonin 5HT1B and 5HT1A receptors in cranial blood vessels.
Reduce neuromuscular inflammation by inhibition of pro-inflammatory neuropeptide release (e.g. substance - P).
Sumatriptan
Triptan. Taken orally at onset of migraine pain. Can be administered orally, nasally or parenteral. Low oral bioavailability and half life of 2.5 hours. Does not cross the BBB. Adverse effects may be due to impairment of the BBB during migraine attacks.
Zolmitriptan
Triptan. Taken orally at the onset of headache pain. Oral bioavailability improved to 50% and half life of 3 hours.
Naratriptan
Triptan. Taken orally at the onset of headache pain. Oral bioavailability improved again to 60% and half life of 5-6 hours.
Ergotamine/s
Structurally similar to amines serotonin, NA and dopamine. Less specificity than Triptans, as interacts with more receptors. Constrict blood vessels, and partially agonizes alpha-adrenergic, 5HT1 and 2 receptors and D2 receptors. Reduces neurogenic inflammation and influences the migraine generator. Avoid if patient has coronary disease, has a small safety margin, and is dangerous in OD. Crosses BBB and 1% bioavailability.
Should triptans or ergotamine be used?
You can use either. Egotamines have an effect on more receptor types (e.g. dopamine), but for some patients this is better.
What opium containing combinations can be used to treat mild migraines?
Paracetamol & codeine, and Ibuprofen & codeine. Offer a slightly high pain relief but have side effects of nausea, drowsiness and constipation. Caffeine also causes cerebral vasoconstriction by antagonizing adenosine receptors.
What can be used to treat nausea resulting from migraine?
Metoclopramide, a D2 receptor antagonist that crosses the BBB.
Domperidone, a D2 receptor antagonist that does not cross the BBB.
Prochlorperazine, a D2 receptor antagonist that belongs to antipsychotic drug class. IV administration to treat status migrainosus.
What is status migrainous?
A migraine that lasts much longer than a usual migraine.
What is migraine?
A chronic disease with episodic exacerbations that decrease with age.
What are the causes of migraine?
- increased excitability of CNS
- meningeal blood vessel dilation
- activation of perivascular sensory trigeminal nerves
- combo of increased pain sensitivity, tissue and vessel swelling, and inflammation
What are the four phases of migraine?
Prodrome - fatigue, difficulty concentrating, light and noise sensitivity
Aura - visual illusions of sparks and light, followed by blind spots
Headache - excruciating pain accompanied by light and noise sensitivity, N&V
Postdrome - persistant sensitivity to light and movement as well as lethargy and difficulty concentrating.
What is the process of a migraine?
Trigeminal nucleus caudis becomes overactive, activating the trigeminal nerve that carries sensory information to the face. The trigeminal nerve also causes blood vessel dilation promoting the release of irritants that stimulate nerve endings near the vessel and cause pain.
