Which medication is indicated for migraine relief but not for prevention?

Sumatriptan is a medication specifically designed for the acute treatment of migraines. It belongs to a class of drugs known as triptans, which act on serotonin receptors to alleviate migraine symptoms effectively. This medication is used to relieve pain and associated symptoms during a migraine attack but is not utilized for the long-term prevention of migraines.

In the context of the other choices, ibuprofen and acetaminophen are both non-prescription medications that can be employed for pain relief during a migraine attack, but they are not specialized migraine treatments like sumatriptan. They do not have the specific mechanism of action that targets the pathways involved in migraines to the extent that triptans do. Amitriptyline, while it can provide preventive measures against migraines, is classified as a tricylcic antidepressant and is prescribed for chronic use to help reduce the frequency and severity of migraine attacks.

Thus, sumatriptan stands out as the medication indicated specifically for the acute relief of migraine symptoms, not meant for prevention, making it the correct choice for this question.