UMEM Educational Pearls

Category: Toxicology


Keywords: ICP, intracranial pressure, antihypertensive, nitroprusside, nitroglycerin, hydralazine (PubMed Search)

Posted: 10/2/2008 by Ellen Lemkin, MD, PharmD (Updated: 3/22/2023)
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Several antihypertensive agents raise intracranial pressure. Normal cerebral blood flow (CBF) is constant within normal cerebral perfusion pressure (CPP) ranges, recalling that CPP=MAP-ICP.

If CPP is outside the range in which autoregulation occurs, e.g. due to a structural lesion, ischemic stroke, or head trauma, CBF decreases and can adversely affect the patient.

  • Nitroprusside
    • Vasodilates both cerebral arteries and veins, increasing ICP
    • Inhibits the normal vasoconstrictive response to hypocapnia
  • Nitroglycerin
    • Causes cerebral venodilation, increasing ICP
    • Impairs vasodilatory response to hypercapnia
  • Hydralazine (varying effects)
    • Vasodilates cerebral arteries > cerebral veins
    • Impairs cerebral autoregulation
  • Nicardipine
    • Other calcium channel blockers increase ICP by vasodilating arteries
    • Has been used to treat vasospasm in SAH
    • Increases cerebral blood flow in patients with SAH and acute stroke

In patients with ischemic stroke or intracerebral pathology, labetalol or esmolol may be used to lower blood pressure without raising ICP. Nicardipine is recommended for use in patients with ischemic stroke or SAH but not in patients with brain injury

If the patient has NO structural abnormalities, but has hypertensive encephalopathy, nitroglycerin, nitroprusside, labetalol, esmolol, or nicardipine may be used.


  1. Tietjen CS, Hurn PD, Ulatowski JA, Kirsch JR. Treatment modalities for hypertensive patient with intracranial pathology: Options and risks. Neurologic Critical Care Feb 1996 42(2):311-22.
  2. Mocco J, Rose JC, Komotar RJ, Mayer SA. Blood pressure management in patients with intracerebral and subarachnoid hemorrhage. Neurosurgical Clinics of North America. 2006 Supplement 1; 25-40.
  3. Adams RE, Powers WJ. Management of hypertension in acute intracerebral hemorrhage. Critical Care Clinic Jan 1997 13(1)132-157.