Drug challenge test for early symptom control in patients with coronary artery spasm: a case report

Background: Calcium channel blockers are the first-line treatment option, followed by long-acting nitrates or nicorandil as second-line medications for patient with coronary artery spasm (CAS). However, there are cases where symptoms cannot be controlled by a combination of these drugs. The drug choice after first- and second-line treatment options is varied and challenging. Case summary: A 70-year-old woman presented to our hospital with complaints of angina at rest. The patient was diagnosed with CAS based on a positive acetylcholine provocation test result. Nitrates were intolerable due to headaches. The combination of calcium channel blocker and nicorandil was not effective in mitigating her symptoms. Four potential symptom relief drugs - trimetazidine, shigyakusan, keishibukuryogan, and denopamine - were prescribed. Each drug was administered for one week, and symptom improvement was assessed one month later. Two drugs (shigyakusan and keishibukuryogan) were effective in relieving her symptoms, but neither was satisfactory on its own. Therefore, these two drugs were combined and added on top of the calcium channel blocker and nicorandil. Her symptoms were well controlled thereafter. Discussion: The drug challenge test, which involves prescribing various types of drugs for short durations to evaluate their effects, may be an effective option for quickly controlling symptoms in patients with refractory CAS who exhibit frequent symptoms.