Can deriphyllin (theophylline) be given in a suspected myocardial infarction (MI) case with hypertension?

Deriphyllin (Theophylline) Should NOT Be Given in Suspected MI with Hypertension

Deriphylline (theophylline) is contraindicated in suspected myocardial infarction, particularly with elevated blood pressure of 190/100 mmHg, as it increases myocardial oxygen demand, causes tachycardia, and can precipitate arrhythmias—all of which worsen outcomes in acute MI. 1

Why Theophylline is Dangerous in MI

Theophylline is a methylxanthine bronchodilator that has several mechanisms that directly harm patients with acute MI:

• Increases heart rate and myocardial oxygen consumption, which worsens ischemia in already compromised myocardium 1, 2
• Causes tachyarrhythmias including ventricular fibrillation, which is a major cause of death in acute MI 1
• Elevates blood pressure further through catecholamine release, compounding the existing hypertension 1
• Increases myocardial workload at a time when the heart muscle is already oxygen-deprived 1

What Should Be Given Instead

For this patient with suspected MI and BP 190/100 mmHg, the appropriate management includes:

Immediate Interventions

• Aspirin 162-325 mg (chewed and swallowed) immediately unless contraindicated 1, 2
• Nitroglycerin sublingual 0.4 mg every 5 minutes up to 3 doses for ongoing chest pain and hypertension, provided systolic BP remains >90 mmHg 1, 2
• Oxygen only if SaO₂ <90%—routine oxygen should be avoided in non-hypoxemic patients 2
• Morphine 4-8 mg IV for pain and anxiety, which also reduces preload 1

Blood Pressure Management in Acute MI

• Beta-blockers are the preferred agents for hypertension in acute MI, as they reduce heart rate, blood pressure, and myocardial oxygen demand 1, 2
• Oral metoprolol 25-50 mg every 6-12 hours can be initiated if no contraindications exist 1
• IV beta-blockers are reasonable for refractory hypertension or ongoing ischemia in hemodynamically stable patients 1

Critical Contraindications to Avoid

Do NOT give beta-blockers if the patient has:

• Signs of heart failure or pulmonary congestion 1
• Evidence of low output state 1
• Heart rate <60 bpm or >110 bpm 1
• Second- or third-degree heart block 1
• Active asthma or reactive airway disease 1

If Bronchospasm is the Concern

If deriphylline was being considered for bronchospasm in this MI patient:

• Selective beta-2 agonists (like albuterol) are safer alternatives if bronchospasm must be treated, though they still carry some cardiac risk 1
• Address the MI first—bronchospasm management is secondary to preventing myocardial death 2
• Consider that "bronchospasm" symptoms may actually be pulmonary edema from left ventricular dysfunction, which requires diuretics and nitrates, not bronchodilators 1

Common Pitfall

The most dangerous error is treating presumed "bronchospasm" or "wheezing" in an MI patient with theophylline or aminophylline derivatives like deriphylline. This can precipitate:

• Fatal ventricular arrhythmias 1
• Extension of infarct size 1
• Cardiogenic shock from increased myocardial oxygen demand 1

Always assume respiratory symptoms in acute MI are cardiac in origin (pulmonary edema) until proven otherwise. 1