SALOMÉ WALTERS

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Blog #2.1

18 Sep 2021, 21:30 Publicly Viewable

The Pathology of a migraine:

A migraine is commonly associated with vomiting, nausea, speech abnormalities, visual scotomas or sometimes even hemianopsia. There are two types of migraines, the first one is the classic migraine which is characterized by the above mentioned symptoms and signs. Triptans, 5-HT agonists and 1D/1B agonists.

The nerve distribution to instracranial and rarely extracranial arteries is involved in a migraine. Calcitonin gene-related peptide (CGRP), especially, releases peptide neurotransmitters and is a very powerful vasodilator. Neurokinin A and Substance P can also be included.

Extravasation of plasma and plasma proteins into the perivascular space causes mechanical stretching, where in the dura, it activates the pain nerve endings. This causes temporal artery pulsations.

The treatment of a migraine:

Ergot alkaloids: Here we can look at Ergotamine and Ergonovine as good examples. These drugs block alpha agonist vasoconstriction and cause a marked smooth muscle contraction. The ergot derivates have mixed partial agonist effects at 5-HT2 receptors and at alpha adrenoceptors.. The effects mentioned above helps to reduce the vasodilation which causes the migraine.

Triptans: Sumatriptan is a good example to look at here. Triptans are the first line drug therapy for acute severe migraines. Triptans should not be used in patients with coronary artery disease because they have the ability to cause coronary vasospasms. These drugs are selective agonists for 5-HT, 1D and 5-HT, 1B receptors. On the presynaptic trigeminal nerve ends they activate these receptors to inhibit the release of the vasodilating peptides.

Beta-blockers: Not for acute attacks, but only for prophylaxis.

Anti-inflammatory analgesics: These drugs only control the pain of the migraine and don’t resolve the migraine. Aspirin is a good example.

Lasmiditan: Highly selective 5-HT 1F receptor agonist which is effective in treating migraines. This agent is much more cardiovascular safe than the triptans. This drug reduces the trigeminal nerve stimulation-induced plasma and plasma protein extravasation in dura vessels. This drug is used in acute migraines.

Calcium channel blockers: For prophylaxis only.