What is the management for myocardial infarction suspected to be induced by Buscopan (hyoscine butylbromide)?

Management of Buscopan-Induced Myocardial Infarction

Treat Buscopan-induced myocardial infarction identically to any acute MI with immediate reperfusion therapy (primary PCI within 90 minutes or fibrinolysis within 30 minutes), while discontinuing the offending agent and providing aggressive hemodynamic support if hypotension is present. 1, 2

Immediate Recognition and Drug Discontinuation

• Stop Buscopan immediately upon suspicion of myocardial infarction, as hyoscine butylbromide can cause both hypotension and myocardial ischemia through hemodynamic instability 3
• Recognize that the mechanism may be either coronary spasm with cardiogenic shock or myocardial ischemia secondary to profound hypotension—both require identical urgent reperfusion strategies 3
• Obtain a 12-lead ECG within 10 minutes of symptom onset to identify ST-segment elevation (≥1 mm in contiguous leads) or new left bundle branch block 1, 2
• Initiate continuous cardiac monitoring immediately, as ventricular fibrillation and life-threatening arrhythmias are common early complications 4, 1

Immediate Pharmacological Management

• Administer aspirin 160-325 mg orally immediately upon diagnosis 4, 1, 2
• Give a P2Y12 inhibitor (ticagrelor or prasugrel preferred over clopidogrel) 1
• Provide intravenous morphine 4-8 mg with additional 2 mg doses every 5 minutes until pain is relieved, as pain causes sympathetic activation that increases cardiac workload 4, 1
• Administer sublingual nitroglycerin only if systolic blood pressure is ≥90 mmHg, as Buscopan-induced hypotension is a critical concern and nitrates will worsen hemodynamic collapse 2, 3
• Initiate anticoagulation with unfractionated heparin, enoxaparin, or bivalirudin according to standard MI protocols 1
• Provide supplemental oxygen only if arterial oxygen saturation is <90%, as routine oxygen is not indicated when SaO₂ ≥90% 1, 2

Hemodynamic Support for Buscopan-Induced Hypotension

• Aggressively treat hypotension with intravenous fluids (normal saline boluses), as hypotension is the most unfavorable side effect of hyoscine and may be the primary mechanism of myocardial ischemia 3
• Consider inotropic agents (dopamine or norepinephrine) if hypotension persists despite fluid resuscitation, particularly if cardiogenic shock develops 4
• Insert an intra-aortic balloon pump if cardiogenic shock is present and refractory to medical management while preparing for urgent revascularization 4, 1
• Monitor arterial pressure invasively in patients with cardiogenic shock to guide therapy 4

Reperfusion Strategy (Do Not Delay)

• Alert the cardiac catheterization laboratory immediately for primary PCI, which must be performed within 90 minutes of first medical contact 1, 2
• Do not wait for cardiac biomarker results when ECG shows clear ST-segment elevation—reperfusion therapy takes absolute priority 1, 2
• Consider fibrinolytic therapy only if PCI cannot be performed within 120 minutes, with door-to-needle time ≤30 minutes 1, 2
• Administer high-dose intravenous heparin during primary PCI 4

Post-Reperfusion Management

• Initiate intravenous beta-blocker therapy followed by oral therapy, as beta-blockers reduce morbidity and mortality in acute MI 4, 5
• Start ACE inhibitor therapy, particularly if left ventricular dysfunction is present 4, 5
• Perform echocardiography to assess ventricular function, wall motion abnormalities, and exclude mechanical complications 1
• Continue aspirin indefinitely at 160-325 mg daily 4

Critical Pitfalls to Avoid

• Do not administer nitrates if significant hypotension is present (systolic BP <90 mmHg), as this will precipitate cardiovascular collapse in the setting of Buscopan-induced hemodynamic instability 2, 3
• Do not delay reperfusion therapy to differentiate between coronary spasm versus hypotension-induced ischemia—both require immediate revascularization and the distinction can be made after stabilization 3
• Avoid calcium channel blockers, as they have not been shown to reduce mortality in acute MI and may worsen hypotension 4
• Do not use prophylactic lidocaine, as it increases the risk of asystole without mortality benefit 4

Special Monitoring Considerations

• Monitor for tachycardia, which is a common antimuscarinic side effect of Buscopan and may worsen myocardial oxygen demand 6, 7
• Watch for urinary retention and other anticholinergic effects that may complicate post-MI care 6, 7
• Recognize that Buscopan is contraindicated in patients with tachycardia, angina, and cardiac failure according to its product monograph—this patient population requires intensive cardiac monitoring 7

Long-Term Management

• Continue aspirin, beta-blocker, and ACE inhibitor therapy indefinitely 4, 5
• Target LDL cholesterol <100 mg/dL with statin therapy 4
• Perform risk stratification with exercise testing at 4-7 days (submaximal) or 10-14 days (symptom-limited) post-MI 4