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 (ED).

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 blood pressure (BP), continuous electrocardiogram (ECG), pulse and respirations 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 medical team. Consider recommencing the infusion at a lower rate.
Therapeutic drug range monitoring should be considered beyond the ED if the patient is started on maintenance dosing.

Seizure medication preparation

Drug	Route	Dose (all ages)	Diluent	Volume of Diluent	Precautions
Midazolam (internal WA Health only) (ampoule strength 5 mg/mL)	Buccal Intranasal	0.3 mg/kg Maximum 10 mg/dose	Nil	Neat	Use atomiser for intranasal administration. See administration section in the monograph.
Midazolam (internal WA Health only) (ampoule strength 5 mg/mL)	Intravenous Intraosseous	0.15 mg/kg Maximum 10 mg/dose	Sodium chloride 0.9%	Draw up 2 mL of midazolam (10 mg) and add 8 mL sodium chloride 0.9% to give 10 mg in 10 mL (1 mg/mL).	Give over at least 2 minutes.
Midazolam (internal WA Health only) (ampoule strength 5 mg/mL)	Intramuscular	0.15 mg/kg Maximum 10 mg/dose	Nil	Neat	Consider muscle site appropriate to the age of child and volume to be administered.
Diazepam (internal WA Health only) (liquid strength 10 mg/10 mL)	Rectal	0.5 mg/kg Maximum Dose: <12 years: 10 mg/dose >12 years: 20 mg/dose	Nil	Neat	Use oral liquid rectally. See administration section in the monograph.
Diazepam (internal WA Health only) (ampoule strength 10 mg/2 mL)	Intravenous Intraosseous	0.25 mg/kg Maximum 10 mg/dose	Nil	Neat	Give over at least 3 to 5 minutes.
Clonazepam (internal WA Health only) (ampoule strength 1 mg/mL)	Intravenous	0.05 mg/kg Repeat after 15 minutes if necessary. Maximum 1 mg/dose	Supplied Water for injection	Draw up 1 mL of clonazepam (1 mg) and add 1 mL of diluent to give 1 mg in 2 mL (0.5 mg/mL).	Give 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) (ampoule strength 50 mg/mL) IV loading dose: 20 mg/kg Maximum dose = 1.5 g	Sodium chloride 0.9% ONLY (not compatible with glucose or other drugs, insert 2nd IV line)	Children ≤ 30 kg 100 mL (add drug directly into a 100 mL bag of sodium chloride 0.9%) Children > 30 kg 250 mL (add drug directly into a 250 mL bag of sodium chloride 0.9%)	Infuse over 20 minutes if dose is 1 g or less. Infuse over 30 minutes if dose is greater than 1 g (maximum 1.5 g) (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. Use diluted solution immediately, infusion stable for 2 hours after dilution. Use inline filter where possible. 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 (Phenobarbitone) (internal WA Health only) (ampoule 200 mg/mL) IV loading dose: 20 mg/kg Maximum dose = 1 g	Water for injections	Dilute to 20 mg/mL with water for injections³	Over 20 minutes	Respiratory depression Hypotension Incompatible with many drugs Avoid extravasation Effects are potentiated by concurrent use of other barbiturates or benzodiazepines
Midazolam (internal WA Health only) Continuous infusion: 50-250 microg/kg/hr (Up to 1000 microg/kg/hr)	Sodium chloride 0.9%	Standard concentration Preparations: Child ≤ 10kg: 15 mg in 30 mL sodium chloride 0.9% Child > 10kg: 50 mg in 50 mL sodium chloride 0.9%	Continuous infusion	Should be used in resuscitation with continuous monitoring. Referral to PCC is mandatory. Higher rates may require patient intubation and ventilation
Levetiracetam⁵ (vial 500 mg/5 mL) IV loading dose: 40 mg/kg Maximum dose = 3 g	Sodium chloride 0.9%	Dilute to 50 mg/mL	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
Phenobarbital (phenobarbitone) Paediatric Injectable Guidelines Online. The Royal Children’s Hospital Melbourne. 2024 Available from: Phenobarbital (phenobarbitone) | Paediatric Injectable Guidelines Online (health.wa.gov.au)
Status Epilepticus management Algorithms Advanced Paediatric Life Support The Practical Approach 7th Edition’, published 2024. Available from: Algorithms | Status epilepticus (apls.org.au)
Levetiracetam AMH CDC Last Updated July 2024, Cited: 8 October 2024.] Available from: Levetiracetam - AMH Children's Dosing Companion (health.wa.gov.au)

Related CAHS internal policies, procedures and guidelines

Clonazepam Monograph – Medication Management Manual (internal WA Health only)

Diazepam – Medication Management Manual (internal WA Health only)

Intramuscular (IM) Injections – Clinical Practice Manual (internal WA Health only)

Midazolam – Medication Management Manual (internal WA Health only)

Phenobarbital (Phenobarbitone) – Medication Management Manual (internal WA Health only)

PHENYTOIN– Medication Management Manual (internal WA Health only)

Endorsed by:	Drug and Therapeutics Committee	Date:	Jun 2024
		Review date:	Apr 2027

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