The patient's clinical presentation of a unilateral, throbbing headache associated with photophobia and nausea is characteristic of a migraine. The question asks for an abortive therapy, which is a medication taken to stop a migraine attack after it has started. Sumatriptan is a serotonin (5-HT1B/1D) receptor agonist (a "triptan") and is a first-line abortive treatment for moderate-to-severe migraine attacks. It works by causing vasoconstriction of cranial arteries and inhibiting the release of vasoactive neuropeptides. The other medications listed are used for migraine prophylaxis (prevention), not for treating an acute attack.

B. Gabapentin: This is an anticonvulsant medication sometimes used off-label for migraine prophylaxis, not for aborting an acute attack.

C. Amitriptyline: This is a tricyclic antidepressant that is established as an effective agent for migraine prophylaxis.

D. Propranolol: This beta-blocker is a first-line, evidence-based medication used for the prophylaxis of episodic migraines.

E. Diltiazem: This calcium channel blocker is not a standard first-line therapy for either abortive or prophylactic treatment of migraine.

1. Marmura

M. J.

Silberstein

S. D.

& Schwedt

T. J. (2015). The acute treatment of migraine in adults: the american headache society evidence assessment of migraine pharmacotherapies. Headache: The Journal of Head and Face Pain

55(1)

3–20. (In Table 2

"Triptans

" including sumatriptan

are listed with a Grade A recommendation as effective for acute migraine treatment). https://doi.org/10.1111/head.12499

2. Silberstein

S. D.

Holland

S.

Lipton

R. B.

& Dodick

D. W. (2012). Evidence-based guideline update: Pharmacologic treatment for episodic migraine prevention in adults: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Headache Society. Neurology

78(17)

1337–1345. (In Table 2

propranolol and amitriptyline are listed as having Level A evidence for migraine prevention. Gabapentin is mentioned as having inadequate evidence to support its use). https://doi.org/10.1212/WNL.0b013e3182535d20

3. VanderPluym

J. H.

Halker Singh

R. B.

& Urtecho

M. (2021). Acute Treatments for Episodic Migraine in Adults: A Systematic Review and Meta-analysis. JAMA

325(23)

2357–2369. (This meta-analysis confirms that triptans are highly effective for acute migraine treatment

specifically for pain freedom at 2 hours). https://doi.org/10.1001/jama.2021.7939

4. University of California

San Francisco (UCSF) Headache Center. (n.d.). Medications for Migraine and Headache. UCSF Department of Neurology. (This educational resource clearly distinguishes between "Abortive Medications" like triptans and "Preventive Medications" like beta-blockers

antidepressants

and anti-seizure drugs). Retrieved from https://headache.ucsf.edu/medications-migraine-and-headache (Section: "Abortive Medications" and "Preventive Medications").