What to give for chest pain if nitroglycerin (nitro) doesn't work?

Management of Chest Pain When Nitroglycerin Doesn't Work

For chest pain that doesn't respond to nitroglycerin, intravenous morphine is the recommended next-line treatment, particularly for persistent pain in patients with suspected acute coronary syndrome. 1

Initial Assessment and Management

• When chest pain is unimproved or worsening 5 minutes after taking one dose of sublingual nitroglycerin, patients should immediately call 9-1-1 1
• For patients with chronic stable angina, if symptoms are not completely resolved after one nitroglycerin dose, they may repeat nitroglycerin every 5 minutes for a maximum of 3 doses, but should call 9-1-1 if symptoms persist 1
• Response to nitroglycerin should not be used as a diagnostic test for coronary artery disease, as studies show it does not reliably distinguish between cardiac and non-cardiac chest pain 2, 3

Pharmacological Management

When Nitroglycerin Fails:

1. Intravenous Morphine

   • EMS providers should administer intravenous morphine for persistent chest pain in patients diagnosed with STEMI (Class IIa, LOE C) 1
   • Morphine may be considered for undifferentiated chest pain unresponsive to nitroglycerin (Class IIb, LOE C) 1
   • Morphine should be titrated according to pain severity, individual patient factors, and other medications given 1
   • Caution: Morphine should be used carefully in unstable angina/NSTEMI due to association with increased mortality in registry data 1

2. Beta-Blockers

   • Intravenous beta-blockers are effective for suspected myocardial ischemia, particularly with tachycardia and hypertension 1
   • They can help reduce cardiac workload and oxygen demand 1

3. Additional Nitroglycerin Options

   • For patients with ongoing ischemic pain, consider switching to intravenous nitroglycerin for continuous therapy 4
   • Intravenous nitroglycerin can be effective for rest angina refractory to other antianginal agents, including long-acting nitrates 4
   • Dose escalation may be necessary if tolerance develops during continuous administration 4

Special Considerations

Cocaine-Associated Chest Pain

• For cocaine-associated chest pain unresponsive to nitroglycerin:
  • Benzodiazepines are first-line treatment 1
  • Calcium channel blockers may be considered if patients don't respond to benzodiazepines and nitroglycerin, but should not be used as first-line treatment 1
  • Phentolamine (an alpha-antagonist) may be beneficial for cocaine-induced coronary vasoconstriction 1

Elderly Patients on Anticoagulation

• For elderly patients on anticoagulation therapy with persistent chest pain:
  • Avoid adding aspirin due to increased bleeding risk, especially in those ≥65 years 5
  • Consider morphine for pain relief when nitroglycerin is insufficient 5

Pitfalls to Avoid

• Don't delay EMS activation if chest pain persists after nitroglycerin administration 1
• Don't assume chest pain that responds to nitroglycerin is cardiac in origin, or that non-response indicates non-cardiac pain 2, 3
• Don't administer nitrates to patients with:
  • Systolic blood pressure <90 mmHg or 30 mmHg below baseline 1
  • Right ventricular infarction 1
  • Recent use of PDE-5 inhibitors (within 24-48 hours) 1
• Use nitrates with extreme caution in patients with inferior STEMI and suspected RV involvement 1

Algorithm for Chest Pain Unresponsive to Nitroglycerin

1. Confirm nitroglycerin has been properly administered and given adequate time to work (5 minutes) 1
2. Activate EMS immediately if not already done 1
3. Administer aspirin 162-325 mg (chewed) if not contraindicated 1
4. Consider IV morphine for pain relief 1
5. Consider IV beta-blockers if tachycardic or hypertensive 1
6. Obtain 12-lead ECG as soon as possible 1
7. Transport rapidly to appropriate cardiac facility 1

By following this approach, healthcare providers can effectively manage patients with chest pain that doesn't respond to nitroglycerin, potentially improving outcomes in acute coronary syndromes.