Dexmedetomidine

Dexmedetomidine (trade names Precedex, Dexdor) is a sedative medication used by intensive care units and anesthetists. It is relatively unusual in its ability to provide sedation without causing respiratory depression. Like clonidine, it is an agonist of α2-adrenergic receptors in certain parts of the brain. It is the S-enantiomer of medetomidine, used in veterinary medicine.

Indications
Dexmedetomidine is indicated for sedation of critically ill or injured patients in an intensive care unit setting. Its indication in the US was recently expanded to include nonintubated patient requiring sedation for surgery or procedures short-term. It is also useful as an adjunct for sedation and general anesthesia in the setting of certain operations and invasive medical procedures, such as colonoscopy. There are no absolute contraindications to the use of dexmedetomidine. Limiting its usefulness is the caution that the drug cannot be bolused due to concerns about peripheral α2-receptor stimulation with resulting hypertension and bradycardia, combined with its current high cost relative to generic medications such as propofol, fentanyl and midazolam which can achieve similar clinical effects.

Intensive care unit sedation
Compared to midazolam, dexmedetomidine was similarly effective for sedation, but shortened the time to extubation. It was associated with less delirium, tachycardia and hypotension, but more bradycardia. It also seemed to be superior to lorazepam for ventilated patients in the intensive care unit. Compared to midazolam, dexmedetomidine is superior due to reduced intensive care costs. The reduced costs are due to a reduction in intensive care unit stay as well as reduced mechanical ventilation.

Procedural sedation
Dexmedetomidine has sedative, analgesic, sympatholytic, and anxiolytic effects that blunt many of the cardiovascular responses in the perioperative period. It reduces the requirements for volatile anesthetics, sedatives and analgesics without causing significant respiratory depression.

Other
Dexmedetomidine may be useful for the treatment of the deleterious cardiovascular effects of acute cocaine intoxication and overdose. Dexmedetomidine may also offer a new paradigm in the pharmacologic treatment of symptoms of distress (intractable pain, agitation or delirium) at the end of life. Recently, an investigator initiated IND was approved by the FDA to examine the use of dexmedetomidine in treating cancer patients at the end of life who are suffering from intractable pain, agitation or delirium.

Dosage and administration
Intravenous infusion of dexmedetomidine is commonly initiated with a 1 mcg/kg loading dose, administered over 10 minutes, followed by a maintenance infusion of 0.2–1.0 mcg/kg/hour. There may be great individual variability in the hemodynamic effects (especially on heart rate and blood pressure), as well as the sedative effects of this drug. For this reason, the dose must be carefully adjusted to achieve the desired clinical effect.

Pricing and Patent life
Dexmedetomidine is currently more expensive than off-patent sedatives, such as propofol and midazolam (median per-patient drug acquisition cost was reported as $75for dexmedetomidine vs $60 for midazolam in one study). Dexmedetomidine is expected to lose patent protection in the United States in 2013 at which time the acquisition cost of this drug will likely decrease.