Description

Zolmitriptan, sold under brand names such as Zomig®, is a medication in the triptan class. It is a selective serotonin receptor agonist used for the acute treatment of migraine headaches. Unlike some pain relievers, it is not a preventative medication and is not effective for tension headaches or other types of pain. It is available in various forms, including oral tablets, orally disintegrating tablets (ODTs), and a nasal spray, which can be useful for patients experiencing nausea or vomiting with their migraine.

Indications

Zolmitriptan is specifically indicated for the acute treatment of migraine attacks with or without aura in adults. It is intended to be taken at the onset of a migraine headache.

Mechanism of Action

The mechanism of action of zolmitriptan is centered on its ability to selectively activate specific serotonin receptors, which results in cranial vasoconstriction and the inhibition of pain signal transmission.

1. Serotonin 5-HT1B and 5-HT1D Receptor Agonism: Zolmitriptan is a highly selective agonist at the serotonin 5-HT1B and 5-HT1D receptors. These receptors are found in several key locations involved in the pathophysiology of migraine:
   • Vascular Smooth Muscle: The 5-HT1B receptors are located on the smooth muscle of intracranial blood vessels. During a migraine attack, these vessels are thought to become dilated and inflamed, which contributes to the throbbing pain.
   • Trigeminal Nerve Endings: The 5-HT1D receptors are located on the presynaptic terminals of sensory nerves in the trigeminal system. During a migraine, these nerves release inflammatory neuropeptides, such as calcitonin gene-related peptide (CGRP), which further promote inflammation and pain.
2. Resulting Effects:
   • Cranial Vasoconstriction: By activating the 5-HT1B receptors, zolmitriptan causes the dilated intracranial blood vessels to constrict back to a more normal size. This reduces the throbbing pain of a migraine headache.
   • Inhibition of Neuropeptide Release: By activating the 5-HT1D receptors on the trigeminal nerve endings, zolmitriptan inhibits the release of inflammatory neuropeptides. This action helps to stop the pain-producing inflammatory process.

• • Central Pain Inhibition: Triptans are also thought to have a central effect, modulating pain transmission in the brainstem and spinal cord, which further contributes to their pain-relieving effects.

In summary, zolmitriptan works by a dual mechanism: it reverses the vasodilation of cranial blood vessels and inhibits the release of pain-producing substances from sensory nerves, thereby aborting the migraine attack.