Management of Hypertension in Vyvanse (Lisdexamfetamine) Overdose
Immediate Assessment: Distinguish Emergency from Urgency
In a Vyvanse overdose with hypertension, you must immediately determine whether acute target-organ damage is present—this distinction, not the blood pressure number itself, dictates whether intravenous therapy is required. 1
- Perform a rapid bedside evaluation (within minutes) for neurologic signs (altered mental status, seizures, severe headache with vomiting, visual changes, focal deficits), cardiac signs (chest pain, pulmonary edema), and fundoscopic examination for bilateral retinal hemorrhages, cotton-wool spots, or papilledema. 1
- If acute target-organ damage is present → hypertensive emergency requiring ICU admission and IV therapy. 1
- If no acute target-organ damage → hypertensive urgency managed with oral agents and outpatient follow-up. 1
Management of Hypertensive Emergency (with Target-Organ Damage)
ICU Admission and Monitoring
- Admit immediately to an intensive care unit with continuous arterial-line blood pressure monitoring (Class I recommendation). 1
Blood Pressure Reduction Targets
- First hour: Reduce mean arterial pressure by 20–25% (or systolic BP by ≤25%). 1
- Hours 2–6: Lower to ≤160/100 mmHg if the patient remains stable. 1
- Hours 24–48: Gradually normalize blood pressure. 1
- Avoid systolic drops >70 mmHg to prevent cerebral, renal, or coronary ischemia, especially in chronic hypertensives with altered autoregulation. 1
First-Line Intravenous Therapy
For sympathomimetic-induced hypertensive emergencies (including amphetamine overdose like Vyvanse), benzodiazepines should be administered first to reduce sympathetic hyperactivity before any specific antihypertensive agent. 1, 2
- Benzodiazepines (e.g., lorazepam 2–4 mg IV or diazepam 5–10 mg IV) are the initial treatment because they address the underlying sympathetic surge driving the hypertension. 1, 2
- If additional blood pressure control is needed after benzodiazepines, use phentolamine, nicardipine, or nitroprusside—never beta-blockers. 1, 2
Why Avoid Beta-Blockers in Sympathomimetic Overdose
- Beta-blockers are absolutely contraindicated in cocaine or amphetamine intoxication because unopposed alpha-adrenergic stimulation can worsen hypertension and cause coronary vasoconstriction. 1, 2
- Labetalol, despite having both alpha and beta-blocking properties, should be avoided in this specific context. 1
Preferred IV Agents After Benzodiazepines
Nicardipine is the preferred second-line agent for sympathomimetic-induced hypertensive emergencies:
- Start at 5 mg/h IV infusion, titrate by 2.5 mg/h every 15 minutes to a maximum of 15 mg/h. 1
- Nicardipine preserves cerebral blood flow, does not raise intracranial pressure, and allows predictable titration. 1
- Onset of action: 5–15 minutes; duration: 30–40 minutes. 1
Phentolamine (alpha-blocker) is an alternative:
- Dose: 5–10 mg IV bolus, repeat every 10 minutes as needed. 3, 4, 5
- Directly antagonizes alpha-adrenergic vasoconstriction from sympathomimetics. 4, 5
Sodium nitroprusside is a last-resort option:
- Use only if other agents fail; requires thiosulfate co-administration when infusion ≥4 µg/kg/min or >30 minutes to prevent cyanide toxicity. 1
Management of Hypertensive Urgency (No Target-Organ Damage)
If there is no evidence of acute target-organ damage, intravenous antihypertensives are not indicated and can cause harm through precipitous blood pressure drops. 1, 2
Oral Therapy Approach
- Benzodiazepines remain first-line to address sympathetic hyperactivity even in urgency. 1, 2
- After benzodiazepine administration, if blood pressure remains elevated, initiate oral antihypertensives:
Blood Pressure Targets
- First 24–48 hours: Gradually reduce to <160/100 mmHg. 1, 2
- Subsequent weeks: Aim for <130/80 mmHg. 1, 2
- Avoid rapid lowering to prevent cerebral, renal, or coronary ischemia. 1, 2
Observation and Follow-Up
- Observe for at least 2 hours after medication administration to assess efficacy and safety. 2
- Arrange outpatient follow-up within 2–4 weeks. 1, 2
Specific Considerations for Sympathomimetic Overdose
Coronary Ischemia
- If chest pain or ECG changes suggest acute coronary syndrome, add nitroglycerin IV (5–100 µg/min) and aspirin after benzodiazepines. 2
- Nitroglycerin reduces myocardial oxygen demand and improves coronary perfusion. 1
Agitation and Seizures
- Benzodiazepines serve dual purposes: controlling agitation/seizures and reducing sympathetic-driven hypertension. 1
- If seizures occur, administer lorazepam 4 mg IV followed by levetiracetam 1500 mg IV or fosphenytoin 20 mg PE/kg IV. 1
Volume Status
- Sympathomimetic overdose often causes volume depletion from diaphoresis and hyperthermia; ensure adequate hydration before administering ACE inhibitors or other agents that can cause precipitous drops. 1, 2
Critical Pitfalls to Avoid
- Do not use beta-blockers (including labetalol) in sympathomimetic overdose due to unopposed alpha-stimulation. 1, 2
- Do not use immediate-release nifedipine—it causes unpredictable precipitous drops, stroke, and death. 1, 2
- Do not use IV antihypertensives for hypertensive urgency—oral therapy is safer and appropriate. 1, 2
- Do not rapidly normalize blood pressure—altered cerebral autoregulation in chronic hypertensives predisposes to ischemic injury. 1
- Do not treat the blood pressure number alone—many elevations are transient and resolve when the underlying sympathomimetic effect wanes. 1
Post-Stabilization Management
- After acute stabilization, address the underlying overdose with supportive care, activated charcoal if within 1 hour of ingestion, and psychiatric evaluation if intentional. 3, 6
- Screen for secondary hypertension causes if the patient has a history of malignant hypertension (20–40% have identifiable causes). 1
- Emphasize medication adherence and safe storage to prevent future overdose. 1