In this section:
- Precedex dosing
- Time to onset
- Initiation and maintenance dosing
- Transitioning to Precedex
- Important pharmacodynamic properties
- Precedex dosing should be individualized and titrated to the desired clinical effect.
- Precedex is not indicated for infusions lasting longer than 24 hours.
- Precedex should be administered using a controlled infusion device.
Time to onset
- Following infusion, Precedex exhibits a rapid distribution phase with a half-life of about 6 minutes.1
- A loading infusion of 1 mcg/kg over a 10-minute period provides onset of sedation typically within 10 to 15 minutes after the start of the infusion.5 If a loading dose is not used, time to onset of the sedative effect may be extended.
Initiation and maintenance dosing
Precedex is generally initiated with a loading dose of 1 mcg/kg over 10 minutes for both procedural sedation and ICU sedation.1
However, coadministration of Precedex with anesthetics, sedatives, hypnotics and opioids can enhance the pharmacodynamic effects of these agents. Specific studies have confirmed these effects with sevoflurane, isoflurane, propofol, alfentanil and midazolam.
Therefore, a decrease in the dosage of Precedex or the concomitant agent may be required.
In patients already sedated with other anesthetics, sedatives, hypnotics or opioid analgesics, a loading dose may not be necessary.
Prior to initiating a loading dose, consideration should be given to the existing level of sedation and condition of the patient.
- For ICU sedation
Maintenance dosing of Precedex is initiated at 0.4 mcg/kg/hr and titrated over a dose range of 0.2 to 0.7 mcg/kg/hr.1
- For sedation during surgical and other procedures
After administration of a 1 mcg/kg loading dose, the maintenance dose of Precedex is initiated at 0.6 mcg/kg/hr and titrated to achieve the desired clinical effect, with doses ranging from 0.2 to 1 mcg/kg/hr.1
In pivotal clinical trials, most patients were started at maintenance doses of 0.4 to 0.6 mcg/kg/hr and titrated up or down to the desired level of sedation.
Dose reductions of concomitant sedative agents or opioid analgesics should be considered, in accordance with their respective dosing instructions and recommendations.
The tables in this section show recommended Precedex dosing for ICU sedation and for sedation during surgical and other procedures.
Transitioning to Precedex from other IV sedative agents
Transitioning to Precedex involves maintaining a balance between adding Precedex and decreasing other preexisting sedatives and/or opioids due to the additive pharmacodynamic effects. This is important to know so that preexisting sedative agents are not titrated downward too quickly before the sedative effects of Precedex are observed, or too slowly, such that patients are oversedated.
- Generally, initiate Precedex maintenance infusion at 0.4 mcg/kg/hr. The titration range for Precedex in the ICU is 0.2 to 0.7 mcg/kg/hr.1
- Full sedative effect of Precedex is generally achieved in 20 to 30 minutes.5
- Titrate down other concomitant sedatives in parallel to the onset of Precedex per their different pharmacokinetic/pharmacodynamic profiles.
- Decreasing/discontinuing the patient’s previous IV sedative therapy prior to the onset of Precedex could lead to periods of undersedation and an increased potential for agitation.
- Adjusting the Precedex dose too rapidly (i.e., less than 20 to 30 minutes) may not allow Precedex to reach its full sedative effects after each dosage adjustment.5
- Increasing Precedex dosages too rapidly could lead to oversedation and an increased potential for side effects.1
Important pharmacodynamic properties of Precedex to understand when transitioning from other IV sedatives
- Coadministration of anesthetics, sedatives, hypnotics and opioids with Precedex can enhance the pharmacodynamic effects of these agents and a decrease in the dosage of Precedex or the concomitant medication may be required when initiating Precedex. Specific studies have confirmed these effects with sevoflurane, isoflurane, propofol, alfentanil and midazolam.1
- Because of the potential for enhanced pharmacodynamic effects of Precedex in combination with other IV sedatives, it is especially important to wait 20 to 30 minutes after each dosage titration to determine the extent of each dosage modification so as to avoid oversedation and the potential for an increased incidence of side effects.1,5
- With Precedex, the time to onset of some sedative effect is generally 10 to 15 minutes when a 1 mcg/kg loading dose is administered over a 10-minute period. However, if a loading dose is not used, the initiation of a sedative effect may extend beyond 15 minutes.5
Precedex Indications and UsagePrecedex is indicated for:
- Sedation of initially intubated and mechanically ventilated patients during treatment in an intensive care setting. Administer Precedex by continuous infusion not to exceed 24 hours.
- Sedation of non-intubated patients prior to and/or during surgical and other procedures.
Precedex Important Safety Information
- Monitoring: Continuously monitor patients while receiving Precedex.
- Bradycardia and Sinus Arrest: Have occurred in young healthy volunteers with high vagal tone or with different routes of administration, e.g., rapid intravenous or bolus administration.
- Hypotension and Bradycardia: May necessitate medical intervention. May be more pronounced in patients with hypovolemia, diabetes mellitus, or chronic hypertension, and in the elderly. Use with caution in patients with advanced heart block or severe ventricular dysfunction.
- Co-administration with Other Vasodilators or Negative Chronotropic Agents: Use with caution due to additive pharmacodynamic effects.
- Transient Hypertension: Observed primarily during the loading dose. Consider reduction in loading infusion rate.
- Arousability: Patients can become aroused/alert with stimulation; this alone should not be considered as lack of efficacy.
- Prolonged exposure to dexmedetomidine beyond 24 hours may be associated with tolerance and tachyphylaxis and a dose-related increase in adverse events.
- The most common adverse reactions (incidence > 2%) are hypotension, bradycardia, and dry mouth.