RESUMEN
BACKGROUND: Coronary artery spasm is a well-known potential side effect of selective 5-hydroxytryptamine type 1 (5HT1) receptor agonists and, therefore, contraindicated in patients with cardiovascular disease. SARS-CoV-2 vaccination has been associated with myocarditis, mainly in young men. CASE SUMMARY: A 55-year-old man with longstanding cluster headache, treated with the 5HT1-agonist Sumatriptan for ten years, received the mRNA-1273 SARS-CoV-2 booster vaccine. Four days later, he developed severe retrosternal pain several minutes after administering Sumatriptan with electrographic ST-elevation and a raised high-sensitivity cardiac troponin-T (hs-cTnT). Coronary angiogram was normal, but a diagnosis of acute myocarditis and hyperthyroidism secondary to Graves' disease was made. DISCUSSION: We present a case of severe coronary artery spasm induced by a 5HT1-agonist secondary to newly diagnosed Graves' disease and myocarditis. The mRNA-1273 SARS-CoV-2 booster vaccine administered four days before admission probably triggered both immunoreactions.