Which blood pressure (BP) medication should be avoided in cocaine intoxication?

Beta Blockers Should Not Be Used in Cocaine Intoxication

Beta blockers should be avoided in patients with cocaine intoxication due to the risk of potentiating coronary vasospasm through unopposed alpha-adrenergic stimulation, which can worsen hypertension and lead to myocardial ischemia. 1

Pathophysiology of Cocaine Cardiovascular Toxicity

Cocaine affects the cardiovascular system through multiple mechanisms:

• Blocks reuptake of catecholamines (norepinephrine, dopamine)
• Stimulates both alpha and beta-adrenergic receptors
• Causes direct vasoconstriction of coronary arteries
• Increases platelet aggregation and thrombosis risk
• Produces endothelial dysfunction

When a patient with cocaine intoxication presents with hypertension and tachycardia, these effects are primarily due to the stimulation of both alpha and beta receptors by excess catecholamines.

Why Beta Blockers Are Contraindicated

When beta blockers are administered to a patient with cocaine intoxication:

1. They block the beta-adrenergic receptors but leave alpha-adrenergic receptors unaffected
2. This creates "unopposed alpha stimulation" where alpha-mediated vasoconstriction continues without the counterbalancing vasodilatory effects of beta-2 stimulation
3. The result is paradoxical worsening of hypertension and increased coronary artery vasoconstriction 1, 2

This phenomenon can lead to:

• Exacerbation of coronary vasospasm
• Worsening hypertension
• Increased risk of myocardial ischemia and infarction
• Potential for stroke and other end-organ damage

Recommended Alternatives for Managing Cocaine-Induced Hypertension

The 2014 AHA/ACC guidelines and 2023 AHA focused update recommend the following alternatives:

1. First-line: Benzodiazepines - alone or in combination with nitroglycerin for management of hypertension and tachycardia 1

   • Reduces central sympathetic outflow
   • Decreases anxiety and agitation
   • Helps prevent seizures

2. Vasodilators for persistent hypertension or coronary vasospasm:

   • Nitroglycerin
   • Calcium channel blockers
   • Phentolamine (alpha-blocker) 1

3. For life-threatening hyperthermia:

   • Rapid external cooling 1

4. For wide-complex tachycardia or cardiac arrest:

   • Sodium bicarbonate
   • Lidocaine may be reasonable 1

Special Considerations

• The contraindication applies specifically to patients showing signs of acute intoxication (euphoria, tachycardia, hypertension) 1
• For patients with a history of cocaine use but no active intoxication, standard ACS protocols may be followed 1
• Some recent research has questioned the absolute nature of this contraindication, particularly for mixed alpha/beta blockers like labetalol or carvedilol 3, 4, 5, but current guidelines still recommend avoiding all beta blockers during acute intoxication

Common Pitfalls to Avoid

1. Failing to recognize signs of cocaine intoxication in patients presenting with chest pain or hypertension
2. Automatically administering beta blockers as part of standard ACS protocols without checking for cocaine use
3. Confusing the recommendation for acute intoxication versus patients with a remote history of cocaine use
4. Underestimating the potential severity of unopposed alpha stimulation
5. Relying on mixed alpha/beta blockers like labetalol, which are still not recommended by current guidelines during acute intoxication

The evidence strongly supports avoiding beta blockers in patients with signs of acute cocaine intoxication to prevent potentially life-threatening complications from unopposed alpha-adrenergic stimulation.