A 28-year-old graduate student presents with complaints of headache. She has had multiple episodes of severe headache over the past three years. She describes the headache as a pounding pain behind her eyes and along the lateral aspects of her head. Prior to the headaches, she almost always sees small flashes of bright light that form enlarging patterns, then clear over time. She often feels nauseated during the headache and occasionally vomits. She has tried multiple over-the-counter pain medications with minimal relief. She has no other medical problems and takes no other medications. She denies fever, weakness, or loss of sensation. Her vital signs are normal. Physical examination, including a full neurologic examination, is normal. The patient’s headache is interrupted using sumatriptan. This drug acts by activation of which of the following?
A 28-year-old graduate student presents with complaints of headache. She has had multiple episodes of severe headache over the past three years. She describes the headache as a pounding pain behind her eyes and along the lateral aspects of her head. Prior to the headaches, she almost always sees small flashes of bright light that form enlarging patterns, then clear over time. She often feels nauseated during the headache and occasionally vomits. She has tried multiple over-the-counter pain medications with minimal relief. She has no other medical problems and takes no other medications. She denies fever, weakness, or loss of sensation. Her vital signs are normal. Physical examination, including a full neurologic examination, is normal. The patient’s headache is interrupted using sumatriptan. This drug acts by activation of which of the following?
💡 Explanation
## **Core Concept**
The patient's symptoms are characteristic of **migraine headaches**, which are a type of neurological disorder. Migraines are often preceded by **auras**, which can include visual disturbances such as seeing flashes of light. The headaches are typically unilateral, throbbing, and can be accompanied by nausea and vomiting.
## **Why the Correct Answer is Right**
Sumatriptan is a medication used to treat migraine headaches. It acts by activating **5-hydroxytryptamine (5-HT) receptors**, specifically the **5-HT1B and 5-HT1D receptors**. These receptors are found on the blood vessels in the brain and are involved in the regulation of vascular tone. Activation of these receptors leads to **vasoconstriction** of the intracranial blood vessels, which helps to alleviate the headache. Additionally, sumatriptan may also act on the **trigeminal nerve** to inhibit the release of pro-inflammatory neuropeptides, which are involved in the pathophysiology of migraine.
## **Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because sumatriptan does not primarily act by blocking histamine receptors.
* **Option B:** This option is incorrect because sumatriptan does not primarily act by blocking dopamine receptors.
* **Option C:** This option is incorrect because, although some anti-migraine drugs work through effects on calcium channels, sumatriptan's primary mechanism is not through blockade of L-type calcium channels.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **triptans**, such as sumatriptan, are most effective when taken early in the course of a migraine attack, and they are not recommended for patients with cardiovascular disease due to their potential to cause vasoconstriction.
## **Correct Answer:** D. 5-HT1B and 5-HT1D receptors.
✓ Correct Answer: D. Serotonin receptors
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