ADMINISTRATION ROUTES:
IV
ALTERNATIVE NAMES:
Precedex, Dexmedetomidine Viatris
ICU INDICATIONS:
- Agitation or delirium
PRESENTATION AND ADMINISTRATION:
IV:
200 mcg/2 mL vial
Dexmedetomidine must be diluted in 0.9% sodium chloride solution prior to administration. Dilute 400 micrograms (4 mL) of dexmedetomidine with 46 mL of 0.9% sodium chloride to total volume of 50 mL. This gives a solution with concentration 8 mcg/mL
Dexmedetomidine is compatible with the following fluids:
Hartmanns, 5% Dextrose, 0.9% Sodium chloride
Store at room temperature
DOSAGE:
All dosing is weight-based and capped at 100 kg. For patients > 100 kg, use 100 kg in all dosing calculations.
Commence infusion at 1 mcg/kg/hr
Reduce by 0.2 mcg/kg/hr every 30 mins until desired sedation is achieved (see below)
Maintenance infusion range 0.2 - 1.0 mcg/kg/hr
No loading dose is required.
Dexmedetomidine must be administered using a controlled infusion device with dosing individualised and titrated to the desired clinical effect, measured using the Richmond Agitation-Sedation Scale (RASS):
| Score | Term | Description |
|---|---|---|
| +4 | Combative | Overtly combative or violent; immediate danger to self & staff |
| +3 | Very agitated | Pulls on or removes tube(s) or catheter(s) or aggressive behaviour towards staff |
| +2 | Agitated | Frequent non-purposeful movement or patient-ventilator dyssynchrony |
| +1 | Restless | Anxious or apprehensive but movements not aggressive or vigorous |
| 0 | Alert and calm | Spontaneously pays attention to caregiver |
| -1 | Drowsy | Not fully alert but has sustained awakening (>10 sec) with eye contact to voice |
| -2 | Light sedation | Briefly (<10 sec) awakens with eye contact to voice |
| -3 | Moderate sedation | Any movement (but no eye contact) to voice |
| -4 | Deep sedation | No response to voice but any movement to physical stimulation |
| -5 | Unrousable | No response to voice or physical stimulation |
The end point for infusion down-titration should be a target RASS of between -2 (light sedation) and +1 (restless).
Dexmedetomidine is usually co-administered with propofol at the lowest rate required to achieve target sedation. For propofol, this may be 10 - 70 mg/hr (1 - 7 mL/hr).
The maximal infusion rate of dexmedetomidine may be increased up to 1.5 mcg/kg/hr if the patient remains agitated. If this maximal dose is then inadequate, further sedation with other agents (including increased propofol sedation) is required.
Since dexmedetomidine clearance decreases with severity of hepatic impairment, dose reduction should be considered in patients with impaired hepatic function.
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose as in normal renal function
DOSAGE IN PAEDIATRICS:
There have been no clinical studies to establish the safety and efficacy of dexmedetomidine in paediatric patients below 18 years of age. Dexmedetomidine is not recommended for use in this population.
CLINICAL PHARMACOLOGY:
Dexmedetomidine is a relatively selective alpha2-adrenoceptor agonist with sedative properties.
CONTRAINDICATIONS:
- Severe bradycardia
- Second or third-degree AV block (unless paced)
WARNINGS:
Clinically significant episodes of bradycardia and sinus arrest have been associated with dexmedetomidine administration. If bradycardia occurs but dexmedetomidine is still deemed clinically necessary, a low-dose adrenaline infusion may be commenced to counter the bradycardia.
PRECAUTIONS:
General:
Some patients receiving dexmedetomidine have been observed to be rousable and alert when stimulated. This alone should not be considered an evidence of lack of efficacy in the absence of other clinical signs and symptoms.
Caution should be exercised when administering dexmedetomidine to patients with advanced heart block and/or severe ventricular dysfunction. Because dexmedetomidine decreases sympathetic nervous system activity, hypotension and/or bradycardia may be expected to be more pronounced in hypovolaemic patients and in those with diabetes mellitus or chronic hypertension and in the elderly.
In situations where other vasodilators or negative chronotropic agents are administered, co-administration of dexmedetomidine could have an additive pharmacodynamic effect and should be administered with caution.
Transient hypertension has been observed in association with the initial peripheral vasoconstrictive effects of dexmedetomidine. Treatment of the transient hypertension has generally not been necessary, although reduction of the infusion rate may be required.
Laboratory Tests:
No tests in addition to routine ICU tests are indicated
Drug/Laboratory Test Interactions:
None known
IMPORTANT DRUG INTERACTIONS IN ICU:
Co-administration of dexmedetomidine with anaesthetics, sedatives, hypnotics, and opioids is likely to lead to an enhancement of effects
ADVERSE REACTIONS:
Body as a Whole:
Fever, rigors
Cardiovascular system:
Hypotension, hypertension, bradycardia, tachycardia, atrial fibrillation
Gastrointestinal system:
Nausea, vomiting
Respiratory system:
Hypoxia, dry mouth
Metabolic and endocrine system:
Hyperglycaemia, acidosis
Haematological system:
Anaemia