Sumatriptan

Chemical nature and mechanism of action

Chemically, sumatriptan is a synthetic tryptamine derivative. Its pharmacodynamics in migraine are unique and mediated by a dual mechanism affecting both the vascular bed and neurotransmission.

1. Vascular component. The drug acts as a selective agonist of central $5-HT_{1D}$ receptors, which are localized primarily in the cerebral blood vessels. During a migraine attack, excessive pulsation of these vessels occurs, causing excruciating pain. Receptor stimulation leads to marked vasoconstriction (narrowing of vessels). As a result, excessive pulsation decreases, and the headache is relieved.
2. Neuronal component. In addition to its vascular effects, sumatriptan stimulates presynaptic serotonin (5-HT) receptors. This inhibits the release of a specific pain mediator — substance P (Substance P). The reduction in its concentration reliably suppresses pain impulses, providing a powerful analgesic effect.

Pharmacokinetics and administration routes

In clinical practice, three main routes of administration are used: oral (per os), subcutaneous, and intranasal. The choice of form depends on how quickly a clinical result is needed.

• Oral administration. When taken orally, the drug's bioavailability is quite low, at only about 14%. The therapeutic effect in this case begins to develop approximately 30 minutes after intake.
• Subcutaneous administration. If an attack requires emergency relief, the injection route is preferred. With subcutaneous administration, the drug's action starts three times faster — in just 10 minutes.

Regardless of the chosen route of administration, the total duration of pharmacological action lasts for approximately 12 hours, allowing for reliable control of the migraine attack.

Clinical application and safety profile

The main indication for prescribing sumatriptan is the relief of acute migraine attacks. It is considered the drug of choice for patients resistant to conventional non-narcotic analgesics (e.g., NSAIDs). However, its potent vasoconstrictive effect imposes severe limitations on its use.

Adverse effects:

• Cardiovascular system: there is a high risk of coronary vasospasm (this is the main contraindication to use).
• Other effects: nausea, vomiting, systemic dizziness, fatigue, and taste disturbances are common.

Contraindications:

• Coronary artery disease (CAD) — due to the critical risk of coronary vasospasm.
• Liver diseases.
• Pregnancy and lactation.
• Age restrictions: the drug is strictly contraindicated in pediatric practice (in children under 18) and is not prescribed to elderly patients (over 65 years old).

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• The role of substance P (Substance P) in pain impulse transmission during migraines.
• Comparative characteristics of sumatriptan administration routes (oral, intranasal, subcutaneous).
• Reasons for the low bioavailability of the drug (14%) upon per os administration.
• Pathogenesis of migraine and mechanisms of excessive cerebral vessel pulsation.
• Justification for age restrictions when prescribing triptans.

Other topics in the section "Drugs used for cerebral circulatory disorders"

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