Seizure - Medication

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.

Read the full CAHS Emergency Department disclaimer

Aim

To guide staff with the use of seizure medications in the Emergency Department.

Preparation

Prepare infusion immediately before use and discard if not commenced within 30 minutes of preparation. Do not prepare more than required dose.
Check for haziness or precipitation before and throughout the infusion.
Compatibility note: Phenytoin sodium is ONLY compatible with sodium chloride 0.9%. Do not administer with any other drugs or fluids.

Flushing Lines

Flush IV lines before and after Phenytoin sodium administration with sodium chloride 0.9%.
After the drug is given, give the flush at the same rate as the infusion. The volume of flush must be sufficient to clear the line of all remaining drug.

Monitoring patients receiving IV phenytoin sodium, phenobarbital (phenobarbitone) and levetiracetam

Infusion rates are different in ward areas – refer to PCH Medication Monographs (WA Health only).
For the loading dose monitor BP, continuous ECG, pulse and respiration every five minutes during the infusion and for 30 minutes after completion of the flush.
If bradycardia or hypotension occurs, stop the infusion and call the doctor. Consider recommencing the infusion at a lower rate.

Seizure medication preparation

Drug	Route	Diluent	Volume of Diluent	Dose	Precautions
Midazolam (WA Health only) (vial strength 5mg/mL)	Buccal	Nil	Neat	0.3mg/kg Maximum 10mg/dose
Midazolam (WA Health only (vial strength 5mg/mL)	Intravenous Intraosseous	Sodium chloride 0.9%	Draw up 2mL of midazolam (10mg) and add 8mL sodium chloride 0.9% to give 10mg in 10mL (1mg/mL)	0.15mg/kg Maximum 10mg/dose
Midazolam (WA Health only (vial strength 5mg/mL)	Intramuscular	Nil	Neat	0.15mg/kg Maximum 10mg/dose	Consider muscle site appropriate to the age of child and volume to be administered
Diazepam (WA Health only) (vial strength 5mg/5mL)	Rectal	Nil	Neat	0.5mg/kg Maximum 20mg/dose
Diazepam (WA Health only) (vial strength 10mg/2mL)	Intravenous Intraosseous	Nil	Neat	0.25mg/kg Maximum 10mg/dose	Over at least 3 to 5 minutes
Clonazepam (vial strength 1mg/mL)	Intravenous	Use diluent provided (ampoule)	Mix 1mg ampoule with 1 mL of diluent to give a 0.5mg/mL solution	0.05mg/kg Repeat after 15 minutes if necessary Maximum 1mg/dose	Over at least 2 minutes Can cause respiratory depression especially if given quickly or combined with barbiturates or other benzodiazepines

Intravenous infusion preparation

Drug	Diluent	Volume of Diluent	Rate of Administration	Precautions and Side Effects
Phenytoin sodium (WA Health only) (IV loading dose) 20mg/kg Max dose = 1.5g	Sodium chloride 0.9% (not compatible with glucose or other drugs, insert 2nd IV line)	Children ≤ 30kg 100mL (add drug directly into a 100mL bag of sodium chloride 0.9%) Children > 30kg 250mL (add drug directly into a 250mL bag of sodium chloride 0.9%)	Infuse over 20 minutes if dose is 1g or less. Infuse over 30 minutes if dose is greater than 1g (max 1.5g) (controlled using an infusion pump)	See above for flushing lines and monitoring requirements. Take into account any Phenytoin received recently (including orally) Do not prepare more than the required amount Line must be flushed before and after with sodium chloride 0.9% ECG and BP monitoring is essential Reduce the rate of administration if bradycardia or hypotension develop
Phenobarbital (WA Health only) (Phenobarbitone) (IV loading dose) 20mg/kg Max dose =1g	Sodium chloride 0.9% or Glucose 5%	Dilute to 20mg per 1mL of diluent	Over 20 minutes	Respiratory depression Hypotension Incompatible with many drugs Avoid extravasation Effects are potentiated by concurrent use of other barbiturates or benzodiazepines
Midazolam (WA Health only) (continuous infusion)	Sodium chloride 0.9% or Glucose 5%	Midazolam 2.5mg/kg (max 125mg) in 50mL of diluent. (a rate of 1 mL per hour = Child ≤ 50kg: 50 microgram/kg/hour Child > 50kg: 2.5mg/hour)	50-250 microgram/kg/hr	Should be used in ventilated patients in intensive care unit
Levetiracetam (IV loading dose) 40mg/kg Max dose = 3g	Sodium chloride 0.9%	Dilute 1:1 (minimum volume 10mL)	Infuse over 5 minutes	Incompatible with many drugs

References

AMH Children’s Dosing Companion (2020) Australian Medicines Handbook Pty Ltd
Australian Injectable Drugs Handbook (AIDH) - 8th Edition 2020

Endorsed by:	Drug and Therapeutics Committee	Date:	Jun 2020
		Review date:	Apr 2023

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