Dexmedetomidine is an alpha-2 agonist commonly used during neurosurgery due to its unique properties as a sedative and anxiolytic with minimal respiratory depression. Neurosurgical patients frequently come to the operating room on anticonvulsant therapy with a history of seizures. The investigators clinical experience suggests that these patients are resistant to the sedative effects of dexmedetomidine. This effect may represent a pharmacokinetic interaction between the anticonvulsant medications and dexmedetomidine or the higher dexmedetomidine dose requirement could result from abnormal pharmacodynamics due to the underlying seizure disorder. The investigators study aims to investigate the pharmacokinetic and pharmacodynamic differences of dexmedetomidine between patients receiving and not receiving enzyme-inducing anticonvulsant therapy and to identify a potential mechanism for these differences.

Inclusion Criteria:

• Age 18-65, BMI 20-25 kg/m2
• Anticonvulsant Group: Diagnosis of seizure disorder taking carbamazepine or phenytoin for a minimum of 2 weeks
• Control Group: Healthy volunteers taking no medications

Exclusion Criteria:

• Positive urine pregnancy test or lactating
• History of allergy to dexmedetomidine or alpha -2 agonists
• History of liver, renal or thyroid disease
• History of cardiovascular disease including history of arrhythmia or congestive heart failure
• History of drug or alcohol abuse