Dexmedetomidine

Dexmedetomidine
	Adult Indications & Dosage
	Pediatric Indications & Dosage
	Contraindications
	Warnings & Precautions
	Adverse Reactions
	Drug Interactions
	Use in Specific Populations
	Administration & Monitoring
	Overdosage
	Pharmacology
	Clinical Studies
	How Supplied
	Images
	Patient Counseling Information
	Precautions with Alcohol
	Brand Names
	Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chetan Lokhande, M.B.B.S [2]

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Overview

Dexmedetomidine is a general anesthetic that is FDA approved for the {{{indicationType}}} of premedication for anesthetic procedure, nonintubated patients, sedation, intubated/mechanically ventilated ICU patients. Common adverse reactions include cardiovascular: hypertension (12% to 13% ), tachycardia (2% to 5% ), gastrointestinal: nausea (3% to 11% ), xerostomia (3% to 4% )..

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

Cough, Fentanyl- or sufentanil-induced: 0.1 mcg/kg, 0.25 mcg/kg, or 0.5 mcg/kg IV over 5 minutes immediately prior to sufentanil and 0.5 or 1 mcg/kg IV over 10 minutes immediately prior to fentanyl were used in clinical trials.
Cough, Fentanyl- or sufentanil-induced: (combination with midazolam) 0.6 mcg/kg IV over 10 minutes plus midazolam 0.06 mg/kg IV over 5 seconds, administered 2 minutes prior to fentanyl, was used in a clinical trial.
Premedication for anesthetic procedure, Nonintubated patients: initial, loading infusion of 1 mcg/kg IV over 10 minutes; for less invasive procedures (ie, ophthalmic surgery), initial loading infusion of 0.5 mcg/kg IV over 10 minutes may be sufficient.
Premedication for anesthetic procedure, Nonintubated patients: maintenance, 0.6 mcg/kg/hr IV infusion titrated to desired clinical effect with doses ranging from 0.2 to 1 mcg/kg/hr.
Premedication for anesthetic procedure, Nonintubated patients: (awake, fiberoptic intubation) initial loading infusion of 1 mcg/kg IV over 10 minutes, followed by maintenance infusion of 0.7 mcg/kg/hr until endotracheal tube is secured.
Premedication for anesthetic procedure, Nonintubated patients: 1 mcg/kg intranasally, diluted in NS to a total volume of 0.8 mL and administered bilaterally (0.4 mL each nostril), provided effective sedation in a small randomized study.
Sedation, Intubated/mechanically ventilated ICU patients: initial, loading infusion of 1 mcg/kg IV over 10 minutes; no loading dose required when converting from alternate sedative therapy.
Sedation, Intubated/mechanically ventilated ICU patients: maintenance, 0.2 to 0.7 mcg/kg/hr continuous IV infusion titrated to desired clinical effect for a MAX of 24 hours.

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

Anesthetics adverse reaction - Shivering.
Cough, Fentanyl- or sufentanil-induced.
General anesthesia; Adjunct.
Sedation, During awake craniotomy.

Non–Guideline-Supported Use

There is limited information about Off-Label Non–Guideline-Supported Use of Dexmedetomidine in adult patients.

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

Safety and efficacy not established in pediatric patients.
Premedication for anesthetic procedure, Nonintubated patients: 2 mcg/kg IV bolus over 10 minutes, then 1 mcg/kg/hour IV until completion of nuclear medicine imaging was used in a clinical study (mean age, 5.7 years).
Premedication for anesthetic procedure, Nonintubated patients: 0.5 to 1 mcg/kg IV every 3 to 5 minutes (mean total dose, 2.1 mcg/kg; mean infusion rate, 1.5 mcg/kg/hr) provided sedation during EEG testing in a retrospective review (mean age, 5.6 years).
Premedication for anesthetic procedure, Nonintubated patients: initial, 1 to 4.5 mcg/kg IM (mean dose, 2.6 mcg/kg) provided sedation during EEG testing in a retrospective review; a second, lower dose (mean dose, 2 mcg/kg) was given if adequate sedation was not achieved 10 minutes after first dose (mean age, 3.5 years).
Premedication for anesthetic procedure, Nonintubated patients: 1 to 2 mcg/kg intranasally, administered bilaterally, provided effective sedation prior to anesthesia induction in 2 randomized studies (ages, 1 to 8 years).

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

There is limited information about Off-Label Guideline-Supported Use of Dexmedetomidine in pediatric patients.

Non–Guideline-Supported Use

There is limited information about Off-Label Non–Guideline-Supported Use of Dexmedetomidine in pediatric patients.

Contraindications

None

Warnings

Drug Administration

Precedex should be administered only by persons skilled in the management of patients in the intensive care or operating room setting. Due to the known pharmacological effects of Precedex, patients should be continuously monitored while receiving Precedex.

Hypotension, Bradycardia, and Sinus Arrest

Clinically significant episodes of bradycardia and sinus arrest have been reported with Precedex administration in young, healthy adult volunteers with high vagal tone or with different routes of administration including rapid intravenous or bolus administration.
Reports of hypotension and bradycardia have been associated with Precedex infusion. If medical intervention is required, treatment may include decreasing or stopping the infusion of Precedex, increasing the rate of intravenous fluid administration, elevation of the lower extremities, and use of pressor agents. Because Precedex has the potential to augment bradycardia induced by vagal stimuli, clinicians should be prepared to intervene. The intravenous administration of anticholinergic agents (e.g., glycopyrrolate, atropine) should be considered to modify vagal tone. In clinical trials, glycopyrrolate or atropine were effective in the treatment of most episodes of Precedex-induced bradycardia. However, in some patients with significant cardiovascular dysfunction, more advanced resuscitative measures were required.
Caution should be exercised when administering Precedex to patients with advanced heart block and/or severe ventricular dysfunction. Because Precedex decreases sympathetic nervous system activity, hypotension and/or bradycardia may be expected to be more pronounced in patients with hypovolemia, diabetes mellitus, or chronic hypertension and in elderly patients.
In clinical trials where other vasodilators or negative chronotropic agents were co-administered with Precedex an additive pharmacodynamic effect was not observed. Nonetheless, caution should be used when such agents are administered concomitantly with Precedex.

Transient Hypertension

Transient hypertension has been observed primarily during the loading dose in association with the initial peripheral vasoconstrictive effects of Precedex. Treatment of the transient hypertension has generally not been necessary, although reduction of the loading infusion rate may be desirable.

Arousability

Some patients receiving Precedex have been observed to be arousable and alert when stimulated. This alone should not be considered as evidence of lack of efficacy in the absence of other clinical signs and symptoms.

Withdrawal

Intensive Care Unit Sedation

With administration up to 7 days, regardless of dose, 12 (5%) Precedex adult subjects experienced at least 1 event related to withdrawal within the first 24 hours after discontinuing study drug and 7 (3%) Precedex adult subjects experienced at least 1 event 24 to 48 hours after end of study drug. The most common events were nausea, vomiting, and agitation.
In adult subjects, tachycardia and hypertension requiring intervention in the 48 hours following study drug discontinuation occurred at frequencies of <5%. If tachycardia and/or hypertension occurs after discontinuation of Precedex supportive therapy is indicated.

Procedural Sedation

In adult subjects, withdrawal symptoms were not seen after discontinuation of short term infusions of Precedex (<6 hours).

Tolerance and Tachyphylaxis

Use of dexmedetomidine beyond 24 hours has been associated with tolerance and tachyphylaxis and a dose-related increase in adverse reactions [see Adverse Reactions].

Hepatic Impairment

Since Precedex clearance decreases with severity of hepatic impairment, dose reduction should be considered in patients with impaired hepatic function [see Dosage and Administration].

Adverse Reactions

Clinical Trials Experience

Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in clinical trials of another drug and may not reflect the rates observed in practice.
Use of Precedex has been associated with the following serious adverse reactions:

Hypotension, bradycardia and sinus arrest [see Warnings and Precautions]
Transient hypertension [see Warnings and Precautions]

Most common treatment-emergent adverse reactions, occurring in greater than 2% of patients in both Intensive Care Unit and procedural sedation studies include hypotension, bradycardia and dry mouth.

Intensive Care Unit Sedation

Adverse reaction information is derived from the continuous infusion trials of Precedex for sedation in the Intensive Care Unit setting in which 1007 adult patients received Precedex. The mean total dose was 7.4 mcg/kg (range: 0.8 to 84.1), mean dose per hour was 0.5 mcg/kg/hr (range: 0.1 to 6.0) and the mean duration of infusion of 15.9 hours (range: 0.2 to 157.2). The population was between 17 to 88 years of age, 43% ≥65 years of age, 77% male and 93% Caucasian. Treatment-emergent adverse reactions occurring at an incidence of >2% are provided in Table 2. The most frequent adverse reactions were hypotension, bradycardia and dry mouth [see Warnings and Precautions].

This image is provided by the National Library of Medicine.

Adverse reaction information was also derived from the placebo-controlled, continuous infusion trials of Precedex for sedation in the surgical intensive care unit setting in which 387 adult patients received Precedex for less than 24 hours. The most frequently observed treatment-emergent adverse events included hypotension, hypertension, nausea, bradycardia, fever, vomiting, hypoxia, tachycardia and anemia (see Table 3).

In a controlled clinical trial, Precedex was compared to midazolam for ICU sedation exceeding 24 hours duration in adult patients. Key treatment emergent adverse events occurring in dexmedetomidine or midazolam treated patients in the randomized active comparator continuous infusion long-term intensive care unit sedation study are provided in Table 4. The number (%) of subjects who had a dose-related increase in treatment-emergent adverse events by maintenance adjusted dose rate range in the Precedex group is provided in Table 5.

The following adverse events occurred between 2 and 5% for Precedex and Midazolam, respectively: renal failure acute (2.5%, 0.8%), acute respiratory distress syndrome (2.5%, 0.8%), and respiratory failure (4.5%, 3.3%).

Procedural Sedation

Adverse reaction information is derived from the two trials for procedural sedation in which 318 adult patients received Precedex. The mean total dose was 1.6 mcg/kg (range: 0.5 to 6.7), mean dose per hour was 1.3 mcg/kg/hr (range: 0.3 to 6.1) and the mean duration of infusion of 1.5 hours (range: 0.1 to 6.2). The population was between 18 to 93 years of age, 30% ≥65 years of age, 52% male and 61% Caucasian.

Treatment-emergent adverse reactions occurring at an incidence of >2% are provided in Table 6. The most frequent adverse reactions were hypotension, bradycardia, and dry mouth [see Warnings and Precautions (5.2)]. Pre-specified criteria for the vital signs to be reported as adverse reactions are footnoted below the table. The decrease in respiratory rate and hypoxia was similar between Precedex and comparator groups in both studies.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of Precedex. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Hypotension and bradycardia were the most common adverse reactions associated with the use of Precedex during post approval use of the drug.

Drug Interactions

Anesthetics, Sedatives, Hypnotics, Opioids

Co-administration of Precedex with anesthetics, sedatives, hypnotics, and opioids is likely to lead to an enhancement of effects. Specific studies have confirmed these effects with sevoflurane, isoflurane, propofol, alfentanil, and midazolam. No pharmacokinetic interactions between Precedex and isoflurane, propofol, alfentanil and midazolam have been demonstrated. However, due to possible pharmacodynamic interactions, when co-administered with Precedex, a reduction in dosage of Precedex or the concomitant anesthetic, sedative, hypnotic or opioid may be required.

Neuromuscular Blockers

In one study of 10 healthy adult volunteers, administration of Precedex for 45 minutes at a plasma concentration of one ng/mL resulted in no clinically meaningful increases in the magnitude of neuromuscular blockade associated with rocuronium administration.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): C

There are no adequate and well-controlled studies of Precedex use in pregnant women. In an in vitro human placenta study, placental transfer of dexmedetomidine occurred. In a study in the pregnant rat, placental transfer of dexmedetomidine was observed when radiolabeled dexmedetomidine was administered subcutaneously. Thus, fetal exposure should be expected in humans, and Precedex should be used during pregnancy only if the potential benefits justify the potential risk to the fetus.
Teratogenic effects were not observed in rats following subcutaneous administration of dexmedetomidine during the period of fetal organogenesis (from gestation day 5 to 16) with doses up to 200 mcg/kg (representing a dose approximately equal to the maximum recommended human intravenous dose based on body surface area) or in rabbits following intravenous administration of dexmedetomidine during the period of fetal organogenesis (from gestation day 6 to 18) with doses up to 96 mcg/kg (representing approximately half the human exposure at the maximum recommended dose based on plasma area under the time-curve comparison). However, fetal toxicity, as evidenced by increased post-implantation losses and reduced live pups, was observed in rats at a subcutaneous dose of 200 mcg/kg. The no-effect dose in rats was 20 mcg/kg (representing a dose less than the maximum recommended human intravenous dose based on a body surface area comparison). In another reproductive toxicity study when dexmedetomidine was administered subcutaneously to pregnant rats at 8 and 32 mcg/kg (representing a dose less than the maximum recommended human intravenous dose based on a body surface area comparison) from gestation day 16 through weaning, lower offspring weights were observed. Additionally, when offspring of the 32 mcg/kg group were allowed to mate, elevated fetal and embryocidal toxicity and delayed motor development was observed in second generation offspring.

Pregnancy Category (AUS): There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Dexmedetomidine in women who are pregnant.

Labor and Delivery

The safety of Precedex during labor and delivery has not been studied.

Nursing Mothers

It is not known whether Precedex is excreted in human milk. Radio-labeled dexmedetomidine administered subcutaneously to lactating female rats was excreted in milk. Because many drugs are excreted in human milk, caution should be exercised when Precedex is administered to a nursing woman.

Pediatric Use

Safety and efficacy have not been established for Procedural or ICU Sedation in pediatric patients. One assessor-blinded trial in pediatric patients and two open label studies in neonates were conducted to assess efficacy for ICU sedation. These studies did not meet their primary efficacy endpoints and the safety data submitted were insufficient to fully characterize the safety profile of Precedex for this patient population. The use of Precedex for procedural sedation in pediatric patients has not been evaluated.

Geriatic Use

Intensive Care Unit Sedation

A total of 729 patients in the clinical studies were 65 years of age and over. A total of 200 patients were 75 years of age and over. In patients greater than 65 years of age, a higher incidence of bradycardia and hypotension was observed following administration of Precedex [see Warnings and Precautions]. Therefore a dose reduction may be considered in patients over 65 years of age [see Dosage and Administration and Clinical Pharmacology].

Procedural Sedation

A total of 131 patients in the clinical studies were 65 years of age and over. A total of 47 patients were 75 years of age and over. Hypotension occurred in a higher incidence in Precedex-treated patients 65 years or older (72%) and 75 years or older (74%) as compared to patients <65 years (47%). A reduced loading dose of 0.5 mcg/kg given over 10 minutes is recommended and a reduction in the maintenance infusion should be considered for patients greater than 65 years of age.

Hepatic Impairment

Since Precedex clearance decreases with increasing severity of hepatic impairment, dose reduction should be considered in patients with impaired hepatic function [see Dosage and Administration and Clinical Pharmacology].

Gender

There is no FDA guidance on the use of Dexmedetomidine with respect to specific gender populations.

Race

There is no FDA guidance on the use of Dexmedetomidine with respect to specific racial populations.

Renal Impairment

There is no FDA guidance on the use of Dexmedetomidine in patients with renal impairment.

Hepatic Impairment

There is no FDA guidance on the use of Dexmedetomidine in patients with hepatic impairment.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Dexmedetomidine in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Dexmedetomidine in patients who are immunocompromised.

Administration and Monitoring

Administration

There is limited information regarding Dexmedetomidine Administration in the drug label.

Monitoring

There is limited information regarding Dexmedetomidine Monitoring in the drug label.

IV Compatibility

There is limited information regarding the compatibility of Dexmedetomidine and IV administrations.

Overdosage

The tolerability of Precedex was studied in one study in which healthy adult subjects were administered doses at and above the recommended dose of 0.2 to 0.7 mcg/kg/hr. The maximum blood concentration achieved in this study was approximately 13 times the upper boundary of the therapeutic range. The most notable effects observed in two subjects who achieved the highest doses were first degree atrioventricular block and second degree heart block. No hemodynamic compromise was noted with the atrioventricular block and the heart block resolved spontaneously within one minute.
Five adult patients received an overdose of Precedex in the intensive care unit sedation studies. Two of these patients had no symptoms reported; one patient received a 2 mcg/kg loading dose over 10 minutes (twice the recommended loading dose) and one patient received a maintenance infusion of 0.8 mcg/kg/hr. Two other patients who received a 2 mcg/kg loading dose over 10 minutes, experienced bradycardia and/or hypotension. One patient who received a loading bolus dose of undiluted Precedex (19.4 mcg/kg), had cardiac arrest from which he was successfully resuscitated.

Pharmacology


Dexmedetomidine
Systematic (IUPAC) name
(S)-4-[1-(2,3-Dimethylphenyl)ethyl]-3H-imidazole
Identifiers
CAS number	113775-47-6
ATC code	N05CM18
PubChem	68602
DrugBank	DB00633
Chemical data
Formula	Template:OrganicBox atom Template:OrganicBox atom Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox atom Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox Template:OrganicBox
Mol. mass	200.28 g/mol
SMILES	eMolecules & PubChem
Pharmacokinetic data
Bioavailability	?
Protein binding	94%
Metabolism	Near complete hepatic metabolism to inactive metabolites
Half life	2 hours
Excretion	Urinary
Therapeutic considerations
Pregnancy cat.	C(US)
Legal status	[[Prescription drug\|Template:Unicode-only]](US)
Routes	Intravenous infusion only

Mechanism of Action

Precedex is a relatively selective alpha2-adrenergic agonist with sedative properties. Alpha2 selectivity is observed in animals following slow intravenous infusion of low and medium doses (10-300 mcg/kg). Both alpha1 and alpha2 activity is observed following slow intravenous infusion of high doses (≥1000 mcg/kg) or with rapid intravenous administration.

Structure

Precedex (dexmedetomidine hydrochloride) injection is a sterile, nonpyrogenic solution suitable for intravenous infusion following dilution. Precedex (dexmedetomidine hydrochloride) in 0.9% Sodium Chloride Injection is a sterile, nonpyrogenic ready to use solution suitable for intravenous infusion. Dexmedetomidine hydrochloride is the S-enantiomer of medetomidine and is chemically described as (+)-4-(S)-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole monohydrochloride. Precedex has a molecular weight of 236.7 and the empirical formula is C13H16N2 • HCl and the structural formula is:

Dexmedetomidine hydrochloride is a white or almost white powder that is freely soluble in water and has a pKa of 7.1. Its partition coefficient in-octanol: water at pH 7.4 is 2.89.
Precedex Injection is supplied as a clear, colorless, isotonic solution with a pH of 4.5 to 7.0. Each mL contains 118 mcg of dexmedetomidine hydrochloride equivalent to 100 mcg (0.1 mg) of dexmedetomidine and 9 mg of sodium chloride in water and is to be used after dilution. The solution is preservative-free and contains no additives or chemical stabilizers.
Precedex in 0.9% Sodium Chloride Injection is supplied as a clear, colorless, isotonic solution with a pH of 4.5 to 7.0. Each mL contains 4.72 mcg of dexmedetomidine hydrochloride equivalent to 4 mcg (0.004 mg) of dexmedetomidine and 9 mg sodium chloride in water and is ready to be used. The solution is preservative-free and contains no additives or chemical stabilizers.

Pharmacodynamics

In a study in healthy volunteers (N = 10), respiratory rate and oxygen saturation remained within normal limits and there was no evidence of respiratory depression when Precedex was administered by intravenous infusion at doses within the recommended dose range (0.2–0.7 mcg/kg/hr).

Pharmacokinetics

Following intravenous administration, dexmedetomidine exhibits the following pharmacokinetic parameters: a rapid distribution phase with a distribution half-life (t1/2) of approximately 6 minutes; a terminal elimination half-life (t1/2) of approximately 2 hours; and steady-state volume of distribution (Vss) of approximately 118 liters. Clearance is estimated to be approximately 39 L/h. The mean body weight associated with this clearance estimate was 72 kg.
Dexmedetomidine exhibits linear pharmacokinetics in the dosage range of 0.2 to 0.7 mcg/kg/hr when administered by intravenous infusion for up to 24 hours. Table 8 shows the main pharmacokinetic parameters when Precedex was infused (after appropriate loading doses) at maintenance infusion rates of 0.17 mcg/kg/hr (target plasma concentration of 0.3 ng/mL) for 12 and 24 hours, 0.33 mcg/kg/hr (target plasma concentration of 0.6 ng/mL) for 24 hours, and 0.70 mcg/kg/hr (target plasma concentration of 1.25 ng/mL) for 24 hours.

Dexmedetomidine pharmacokinetic parameters after Precedex maintenance doses of 0.2 to 1.4 mcg/kg/hr for >24 hours were similar to the PK parameters after Precedex maintenance dosing for < 24 hours in other studies. The values for clearance (CL), volume of distribution (V), and t1/2 were 39.4 L/hr, 152 L, and 2.67 hours, respectively.

Distribution

The steady-state volume of distribution (Vss) of dexmedetomidine was approximately 118 liters. Dexmedetomidine protein binding was assessed in the plasma of normal healthy male and female subjects. The average protein binding was 94% and was constant across the different plasma concentrations tested. Protein binding was similar in males and females. The fraction of Precedex that was bound to plasma proteins was significantly decreased in subjects with hepatic impairment compared to healthy subjects.
The potential for protein binding displacement of dexmedetomidine by fentanyl, ketorolac, theophylline, digoxin and lidocaine was explored in vitro, and negligible changes in the plasma protein binding of Precedex were observed. The potential for protein binding displacement of phenytoin, warfarin, ibuprofen, propranolol, theophylline and digoxin by Precedex was explored in vitro and none of these compounds appeared to be significantly displaced by Precedex.

Metabolism

Dexmedetomidine undergoes almost complete biotransformation with very little unchanged dexmedetomidine excreted in urine and feces. Biotransformation involves both direct glucuronidation as well as cytochrome P450 mediated metabolism. The major metabolic pathways of dexmedetomidine are: direct N-glucuronidation to inactive metabolites; aliphatic hydroxylation (mediated primarily by CYP2A6) of dexmedetomidine to generate 3-hydroxy-dexmedetomidine, the glucuronide of 3-hydroxy-dexmedetomidine, and 3-carboxy-dexmedetomidine; and N-methylation of dexmedetomidine to generate 3-hydroxy N-methyl-dexmedetomidine, 3-carboxy N-methyl-dexmedetomidine, and dexmedetomidine-N-methyl O-glucuronide.

Elimination

The terminal elimination half-life (t1/2) of dexmedetomidine is approximately 2 hours and clearance is estimated to be approximately 39 L/h. A mass balance study demonstrated that after nine days an average of 95% of the radioactivity, following intravenous administration of radiolabeled dexmedetomidine, was recovered in the urine and 4% in the feces. No unchanged dexmedetomidine was detected in the urine. Approximately 85% of the radioactivity recovered in the urine was excreted within 24 hours after the infusion. Fractionation of the radioactivity excreted in urine demonstrated that products of N-glucuronidation accounted for approximately 34% of the cumulative urinary excretion. In addition, aliphatic hydroxylation of parent drug to form 3-hydroxy-dexmedetomidine, the glucuronide of 3-hydroxy-dexmedetomidine, and 3-carboxylic acid-dexmedetomidine together represented approximately 14% of the dose in urine. N-methylation of dexmedetomidine to form 3-hydroxy N-methyl dexmedetomidine, 3-carboxy N-methyl dexmedetomidine, and N-methyl O-glucuronide dexmedetomidine accounted for approximately 18% of the dose in urine. The N-Methyl metabolite itself was a minor circulating component and was undetected in urine. Approximately 28% of the urinary metabolites have not been identified.

Gender

There was no observed difference in Precedex pharmacokinetics due to gender.

Geriatrics

The pharmacokinetic profile of Precedex was not altered by age. There were no differences in the pharmacokinetics of Precedex in young (18–40 years), middle age (41–65 years), and elderly (>65 years) subjects.

Hepatic Impairment

In subjects with varying degrees of hepatic impairment (Child-Pugh Class A, B, or C), clearance values for Precedex were lower than in healthy subjects. The mean clearance values for patients with mild, moderate, and severe hepatic impairment were 74%, 64% and 53% of those observed in the normal healthy subjects, respectively. Mean clearances for free drug were 59%, 51% and 32% of those observed in the normal healthy subjects, respectively.
Although Precedex is dosed to effect, it may be necessary to consider dose reduction in subjects with hepatic impairment [see Dosage and Administration, Warnings and Precautions].

Renal Impairment

Dexmedetomidine pharmacokinetics (Cmax, Tmax, AUC, t1/2, CL, and Vss) were not significantly different in patients with severe renal impairment (creatinine clearance: <30 mL/min) compared to healthy subjects.

Drug Interactions

In vitro studies: In vitro studies in human liver microsomes demonstrated no evidence of cytochrome P450 mediated drug interactions that are likely to be of clinical relevance.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

Animal carcinogenicity studies have not been performed with dexmedetomidine.
Dexmedetomidine was not mutagenic in vitro, in either the bacterial reverse mutation assay (E. coli and Salmonella typhimurium) or the mammalian cell forward mutation assay (mouse lymphoma). Dexmedetomidine was clastogenic in the in vitro human lymphocyte chromosome aberration test with, but not without, rat S9 metabolic activation. In contrast, dexmedetomidine was not clastogenic in the in vitro human lymphocyte chromosome aberration test with or without human S9 metabolic activation. Although dexmedetomidine was clastogenic in an in vivo mouse micronucleus test in NMRI mice, there was no evidence of clastogenicity in CD-1 mice.
Fertility in male or female rats was not affected after daily subcutaneous injections of dexmedetomidine at doses up to 54 mcg/kg (less than the maximum recommended human intravenous dose on a mcg/m2 basis) administered from 10 weeks prior to mating in males, and 3 weeks prior to mating and during mating in females.

Animal Pharmacology and/or Toxicology

There were no differences in the adrenocorticotropic hormone (ACTH)-stimulated cortisol response in dogs following a single dose of dexmedetomidine compared to saline control. However, after continuous subcutaneous infusions of dexmedetomidine at 3 mcg/kg/hr and 10 mcg/kg/hr for one week in dogs (exposures estimated to be within the clinical range), the ACTH-stimulated cortisol response was diminished by approximately 27% and 40%, respectively, compared to saline-treated control animals indicating a dose-dependent adrenal suppression.

Clinical Studies

The safety and efficacy of Precedex has been evaluated in four randomized, double-blind, placebo-controlled multicenter clinical trials in 1185 adult patients.

=Intensive Care Unit Sedation

Two randomized, double-blind, parallel-group, placebo-controlled multicenter clinical trials included 754 adult patients being treated in a surgical intensive care unit. All patients were initially intubated and received mechanical ventilation. These trials evaluated the sedative properties of Precedex by comparing the amount of rescue medication (midazolam in one trial and propofol in the second) required to achieve a specified level of sedation (using the standardized Ramsay Sedation Scale) between Precedex and placebo from onset of treatment to extubation or to a total treatment duration of 24 hours. The Ramsay Level of Sedation Scale is displayed in Table 9.

In the first study, 175 adult patients were randomized to receive placebo and 178 to receive Precedex by intravenous infusion at a dose of 0.4 mcg/kg/hr (with allowed adjustment between 0.2 and 0.7 mcg/kg/hr) following an initial loading infusion of one mcg/kg intravenous over 10 minutes. The study drug infusion rate was adjusted to maintain a Ramsay sedation score of ≥3. Patients were allowed to receive “rescue” midazolam as needed to augment the study drug infusion. In addition, morphine sulfate was administered for pain as needed. The primary outcome measure for this study was the total amount of rescue medication (midazolam) needed to maintain sedation as specified while intubated. Patients randomized to placebo received significantly more midazolam than patients randomized to Precedex (see Table 10).
A second prospective primary analysis assessed the sedative effects of Precedex by comparing the percentage of patients who achieved a Ramsay sedation score of ≥3 during intubation without the use of additional rescue medication. A significantly greater percentage of patients in the Precedex group maintained a Ramsay sedation score of ≥3 without receiving any midazolam rescue compared to the placebo group (see Table 10).

A prospective secondary analysis assessed the dose of morphine sulfate administered to patients in the Precedex and placebo groups. On average, Precedex-treated patients received less morphine sulfate for pain than placebo-treated patients (0.47 versus 0.83 mg/h). In addition, 44% (79 of 178 patients) of Precedex patients received no morphine sulfate for pain versus 19% (33 of 175 patients) in the placebo group.
In a second study, 198 adult patients were randomized to receive placebo and 203 to receive Precedex by intravenous infusion at a dose of 0.4 mcg/kg/hr (with allowed adjustment between 0.2 and 0.7 mcg/kg/hr) following an initial loading infusion of one mcg/kg intravenous over 10 minutes. The study drug infusion was adjusted to maintain a Ramsay sedation score of ≥3. Patients were allowed to receive “rescue” propofol as needed to augment the study drug infusion. In addition, morphine sulfate was administered as needed for pain. The primary outcome measure for this study was the total amount of rescue medication (propofol) needed to maintain sedation as specified while intubated.
Patients randomized to placebo received significantly more propofol than patients randomized to Precedex (see Table 11).
A significantly greater percentage of patients in the Precedex group compared to the placebo group maintained a Ramsay sedation score of ≥3 without receiving any propofol rescue (see Table 11).

A prospective secondary analysis assessed the dose of morphine sulfate administered to patients in the Precedex and placebo groups. On average, Precedex-treated patients received less morphine sulfate for pain than placebo-treated patients (0.43 versus 0.89 mg/h). In addition, 41% (83 of 203 patients) of Precedex patients received no morphine sulfate for pain versus 15% (30 of 198 patients) in the placebo group.
In a controlled clinical trial, Precedex was compared to midazolam for ICU sedation exceeding 24 hours duration. Precedex was not shown to be superior to midazolam for the primary efficacy endpoint, the percent of time patients were adequately sedated (81% versus 81%). In addition, administration of Precedex for longer than 24 hours was associated with tolerance, tachyphylaxis, and a dose-related increase in adverse events [see Adverse Reactions].

Procedural Sedation

The safety and efficacy of Precedex for sedation of non-intubated patients prior to and/or during surgical and other procedures was evaluated in two randomized, double-blind, placebo-controlled multicenter clinical trials. Study 1 evaluated the sedative properties of Precedex in patients having a variety of elective surgeries/procedures performed under monitored anesthesia care. Study 2 evaluated Precedex in patients undergoing awake fiberoptic intubation prior to a surgical or diagnostic procedure.
In Study 1, the sedative properties of Precedex were evaluated by comparing the percent of patients not requiring rescue midazolam to achieve a specified level of sedation using the standardized Observer’s Assessment of Alertness/Sedation Scale (see Table 12)

Patients were randomized to receive a loading infusion of either Precedex 1 mcg/kg, Precedex 0.5 mcg/kg, or placebo (normal saline) given over 10 minutes and followed by a maintenance infusion started at 0.6 mcg/kg/hr. The maintenance infusion of study drug could be titrated from 0.2 mcg/kg/hr to 1 mcg/kg/hr to achieve the targeted sedation score (Observer’s Assessment of Alertness/Sedation Scale ≤4). Patients were allowed to receive rescue midazolam as needed to achieve and/or maintain an Observer’s Assessment of Alertness/Sedation Scale ≤4. After achieving the desired level of sedation, a local or regional anesthetic block was performed. Demographic characteristics were similar between the Precedex and comparator groups. Efficacy results showed that Precedex was more effective than the comparator group when used to sedate non-intubated patients requiring monitored anesthesia care during surgical and other procedures (see Table 13).
In Study 2, the sedative properties of Precedex were evaluated by comparing the percent of patients requiring rescue midazolam to achieve or maintain a specified level of sedation using the Ramsay Sedation Scale score ≥2 (see Table 9). Patients were randomized to receive a loading infusion of Precedex 1 mcg/kg or placebo (normal saline) given over 10 minutes and followed by a fixed maintenance infusion of 0.7 mcg/kg/hr. After achieving the desired level of sedation, topicalization of the airway occurred. Patients were allowed to receive rescue midazolam as needed to achieve and/or maintain a Ramsay Sedation Scale ≥2. Demographic characteristics were similar between the Precedex and comparator groups. For efficacy results see Table 13.

How Supplied

Precedex Injection

Precedex (dexmedetomidine hydrochloride) injection 200 mcg/2 mL (100 mcg/mL) is available in 2 mL clear glass vials. The strength is based on the dexmedetomidine base. Vials are intended for single use only.

Precedex in 0.9% Sodium Chloride Injection

Precedex (dexmedetomidine hydrochloride in 0.9% Sodium Chloride) injection is available as 200 mcg/50 mL (4 mcg/mL) and 400 mcg/100 mL (4 mcg/mL) in 50 mL and 100 mL clear glass bottles, respectively. Containers are intended for single use only.

Store at controlled room temperature, 25°C (77°F) with excursions allowed from 15 to 30°C (59 to 86°F). [See USP.]

Storage

There is limited information regarding Dexmedetomidine Storage in the drug label.

Images

Drug Images

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Patient Counseling Information

Precedex is indicated for short-term intravenous sedation. Dosage must be individualized and titrated to the desired clinical effect. Blood pressure, heart rate and oxygen levels will be monitored both continuously during the infusion of Precedex and as clinically appropriate after discontinuation.
When Precedex is infused for more than 6 hours, patients should be informed to report nervousness, agitation, and headaches that may occur for up to 48 hours.
Additionally, patients should be informed to report symptoms that may occur within 48 hours after the administration of Precedex such as: weakness, confusion, excessive sweating, weight loss, abdominal pain, salt cravings, diarrhea, constipation, dizziness or light-headedness.

Manufactured and Distributed by:

Hospira, Inc.

Lake Forest, IL 60045 USA

Licensed from:

Orion Corporation

Espoo, Finland

EN-3411

Hospira, Inc., Lake Forest, IL 60045 USA

Precautions with Alcohol

Alcohol-Dexmedetomidine interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

There is limited information regarding Dexmedetomidine Brand Names in the drug label.

Look-Alike Drug Names

There is limited information regarding Dexmedetomidine Look-Alike Drug Names in the drug label.

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.

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