What are the considerations for general anesthesia in patients with recent cocaine use?

Anesthetic Management of Cocaine Users

In patients with recent cocaine use, proceed with general anesthesia if they are clinically non-toxic (normal vital signs, normal ECG, QTc <500ms), but absolutely avoid beta-blockers in those showing signs of acute intoxication due to risk of unopposed alpha-adrenergic stimulation causing fatal coronary vasospasm. 1, 2

Preoperative Assessment and Risk Stratification

Timing Considerations

• Most cocaine-associated myocardial infarctions occur within 3 hours of use, with a 24-fold increased MI risk in the first hour 1
• However, cocaine metabolites (benzoylecgonine) persist up to 24 hours and can cause delayed coronary vasoconstriction, with symptoms potentially occurring 18 hours after use 1
• Urine testing for benzoylecgonine is the most reliable method to detect recent use, as self-reporting significantly underestimates exposure 1

Clinical Toxicity Assessment

Distinguish between acute intoxication versus chronic use without active toxicity:

Signs of acute intoxication (HIGH RISK - consider delaying elective surgery): 1, 2

• Euphoria
• Tachycardia
• Hypertension
• Hyperthermia
• Agitation

Clinically non-toxic (SAFE to proceed): 3

• Normal blood pressure and heart rate
• Normothermic
• Normal or unchanged ECG
• QTc interval <500ms
• Positive urine cocaine metabolites alone without clinical signs

Cardiovascular Complications to Screen For

Evaluate for these cocaine-related cardiac pathologies preoperatively: 1, 2

• Accelerated atherosclerosis (chronic users)
• Myocarditis and cardiomyopathy
• Aortic dissection or coronary artery dissection
• Pulmonary hypertension

Intraoperative Management

Hemodynamic Control - Critical Drug Selection

For hypertension and tachycardia in acute intoxication:

FIRST-LINE: Benzodiazepines ± nitroglycerin 1, 2

• Benzodiazepines address central and peripheral manifestations of cocaine toxicity
• Add nitroglycerin or calcium channel blockers (diltiazem 20mg IV) for persistent hypertension or chest pain 1, 2

AVOID: Beta-blockers in acute intoxication 1, 2

• Class III Harm recommendation: Do not administer beta-blockers to patients with signs of acute cocaine intoxication 1
• Risk of unopposed alpha-adrenergic stimulation causing severe coronary vasospasm 1, 4
• Labetalol is particularly problematic as its beta-blocking effects are more potent than alpha-blocking effects, resulting in unopposed alpha vasoconstriction 4
• Multiple case reports document pulmonary edema and cardiac arrest after beta-blocker administration in cocaine-intoxicated patients 1

CAUTION: Phentolamine (alpha-blocker) 4

• Equal affinity for alpha-1 and alpha-2 receptors may result in significant reflex tachycardia
• Not recommended as first-line agent

Anesthetic Agent Selection

Acceptable agents: 4, 5

• Barbiturates
• Nitrous oxide
• Opioids (fentanyl, others)
• Volatile anesthetics - use with caution due to myocardial depressant effects, especially in patients with cocaine-induced cardiomyopathy 4, 5

Regional anesthesia considerations: 4, 5

• May be preferred if coagulopathies and hypovolemia are corrected preoperatively
• Reduces sympathetic stimulation from general anesthesia

Lidocaine controversy: 4

• As an amide local anesthetic, may have additive effects with cocaine that lower seizure threshold
• Use with caution for arrhythmia management

Vasopressor Management in Chronic Users

Chronic cocaine users may develop catecholamine depletion, causing unexpected hypotension: 6

Preferred vasopressors:

• Direct-acting agents (phenylephrine, noradrenaline) are more effective than indirect-acting agents 6
• Epinephrine use is controversial in the setting of cocaine-induced catecholamine excess 4, 5

Treatment approach:

• Intravenous fluid resuscitation first
• Direct-acting vasopressors if fluids insufficient 6

Special Consideration: Topical Phenylephrine

AVOID topical phenylephrine in cocaine users undergoing ENT/nasal surgery: 1, 7

• Multiple case reports of severe hypertension, pulmonary edema, and death when topical phenylephrine combined with cocaine 1
• One case documented diffuse coronary spasm and cardiogenic shock mimicking STEMI after topical cocaine use in nasal surgery 7
• 10 of 18 surveyed hospitals with large pediatric ENT volumes have abandoned phenylephrine use due to adverse events 1

Evidence for Safety in Non-Toxic Patients

A prospective study of 40 cocaine-positive but clinically non-toxic patients demonstrated:

• No significant difference in intraoperative cardiovascular stability compared to matched controls 3
• Mean arterial pressure, ST segments, heart rate, and temperature were comparable 3
• This supports proceeding with elective surgery in urine-positive but clinically non-toxic patients 3

Postoperative Monitoring

• 90% of complications occur within first 12 hours after presentation 1
• Monitor for arrhythmias (ventricular tachycardia 18%, supraventricular tachycardia 5%, bradyarrhythmias 20%) 1
• Serial vital sign assessment crucial in patients with cardiovascular complications 2
• In-hospital mortality for cocaine-associated MI is low (0%) when appropriately managed 1

Key Pitfalls to Avoid

1. Never administer beta-blockers to patients with signs of acute cocaine intoxication - this is a Class III Harm recommendation 1
2. Do not assume urine-negative status means no risk - metabolites persist 24 hours and delayed effects can occur 1
3. Do not use indirect-acting vasopressors in chronic users with catecholamine depletion 6
4. Avoid topical phenylephrine in any patient with recent cocaine use 1, 7
5. Do not delay treatment assuming "young and healthy" - 72% of cocaine MI patients are nonwhite, 91% are smokers, mean age 38 years 1