midazolam

patient information sheets

short-acting water soluble benzodiazepine which can thus be used intranasally, orally as well as iv, im.
95% prot.bound; T½=2hrs; Vd = 1.1L/kg; Clear. = 6.6ml/min/kg;

see seizures
paediatric:
- intranasal 0.2mg/kg (max. 10mg)
- buccal 0.5mg/kg (max. 10mg)
- iv/im 0.15 mg/kg
adult:
- iv/im 0.15 mg/kg

adults:
- 1-2mg iv bolus
- usually combined with a short acting opiate such as boluses of fentanyl 0.5-1mcg/kg
beware respiratory depression, particularly with iv doses in children, the elderly and those with poor respiratory or CNS function.

induction:
- see induction agents
maintenance of GA in an intubated patient:
- usually an infusion of midazolam combined with morphine
  - make up infusion to concentration of 1mg/ml of each of midazolam & morphine by:
    - 100ml NS, withdraw 10ml and add 120mg of morphine and 120mg midazolam
    - run at 0.02-0.08 ml/kg/hr

Myasthenia gravis
Known sensitivity to benzodiazepines (rare)
Acute narrow angle glaucoma
For procedural sedation - known airway problems/difficulties (e.g. previous airway surgery, previous difficulties with anaesthetic management)
Acute and chronic hypoventilation (e.g. respiratory disease with severe hypoxia or any hypercapnia, obstructive sleep apnoea)
For procedural sedation age < 1 year is a contraindication due to increased risk of airway complications.
- procedures may be more safely performed under general anaesthetic in theatre

must be administered with extreme caution in the presence of:
- Hypotension;
- Respiratory depression (unventilated patients)
- Hypovolaemia
Care is needed during sedation as unconsciousness can occur in some people with relatively small doses.
Some depression of cardiovascular function occurs, especially with higher doses or patients with reduced reserve
dosage should be reduced in patients with liver disease
Midazolam should be used in conjunction with narcotic analgesics as it does not have analgesic properties.
extravasation should be avoided
Intravenous Midazolam should only be used in a setting where there is equipment for continuous monitoring of respiratory and cardiac function.
In children the use of IV or IM Midazolam should be in the resuscitation area only.
Midazolam can enhance the central sedative effects of neuroleptics, tranquillisers, antidepressants, analgesics and anaesthetics.
Ideally the level of sedation should be such that the patient is calm and responsive, ie. to external stimuli. Sedation levels and drug administration rates should be assessed frequently to ‘maintain contact’ with the patient
Administration of midazolam for agitation is a contraindication to placing patients in seclusion until effects have worn off
Patient consent for procedures is not valid after the administration of Midazolam

supportive care with protection of airways and respiration
if patient has not been on benzodiazepines prior, then consider use of benzodiazepine antagonists such as:
- flumazenil
  - Paed 5 mcg/kg per dose titrated to a total dose of 40mcg/kg
  - Adult 300 – 600 mcg
  - BUT MAY PRECIPITATE SEIZURES IN THOSE WITH DEPENDENCY OR WITH POLYPHARMACY OVERDOSES