๐ Key Information Summary
- Seizures occur in approximately 5โ10% of patients in the last days of life, most commonly in those with primary brain tumours, cerebral metastases, or metabolic encephalopathy.
- Existing antiepileptic medications (AEDs) should be continued in the dying patient wherever possible โ switch to subcutaneous, sublingual, buccal, or rectal routes when oral intake ceases.
- Subcutaneous midazolam (0.5 mg/kg over 24 hours via CSCI, or 2.5โ5 mg STAT SC/IM) is the first-line agent for acute seizure management in palliative care.
- Subcutaneous clonazepam (0.5โ1 mg over 24 hours via CSCI) is a second-line or adjunctive agent for refractory or recurrent seizures.
- For patients on valproate, levetiracetam, or phenytoin, equivalent subcutaneous doses can be prepared โ consult a palliative medicine specialist or pharmacist for conversions.
- Rectal diazepam (0.2 mg/kg, up to 10โ20 mg) remains a practical option for breakthrough seizures when no continuous subcutaneous infusion (CSCI) line is in situ.
- Do not routinely discontinue AEDs solely because the patient is dying โ withdrawal may precipitate distressing seizures.
- Seizures in the last days may cause significant distress to family and carers; anticipatory guidance and advance care planning should address seizure risk.
- The goal of treatment is symptom control and comfort โ not seizure freedom per se โ and sedation should be titrated to effect.
- Consultation with a palliative care specialist is recommended for refractory seizures, status epilepticus in the dying, or when medication compatibility with CSCI is uncertain.
- Always consider and correct reversible causes such as hyponatraemia, hypoglycaemia, uraemia, or medication toxicity where consistent with goals of care.
- For Aboriginal and Torres Strait Islander patients, culturally safe communication, family-inclusive decision-making, and access to community palliative care should be prioritised.
Introduction & Australian Context
Seizures in the last days of life represent a distressing symptom for patients, families, and clinicians alike. This topic covers the prevention and management of seizures when oral antiepileptic medications are no longer feasible due to declining consciousness, dysphagia, or the imminence of death.
In Australia, approximately 160,000 people die each year. Of these, an estimated 5โ10% will experience one or more seizures in the final days of life, with higher rates reported in patients with primary brain tumours (up to 30%), cerebral metastases, metabolic encephalopathy, and certain neurodegenerative conditions. Seizures may be focal or generalised and range from subtle myoclonic jerks to overt tonic-clonic convulsions.
The management of seizures at the end of life requires a balance between effective seizure suppression and the avoidance of excessive sedation. The overarching goal is comfort โ not necessarily complete seizure freedom โ and treatment decisions should be guided by the patient's advance care plan, expressed wishes, and the clinical context. Where seizures were previously well controlled on oral antiepileptic drugs (AEDs), continuation of these agents via alternative routes is strongly recommended.
Australian palliative care practice is guided by Palliative Care Australia's National Palliative Care Standards (2018), the Australasian Society of Clinical and Immunology and Allergy (ASCIA) position statements, state-based Palliative Care Clinical Studies Collaborative (PaCCSC) research, and Therapeutic Guidelines: Palliative Care. The Palliative Care Therapeutic Programme (S85) under the Pharmaceutical Benefits Scheme (PBS) facilitates access to essential symptom management medications in the community and inpatient settings.
Continue Antiepileptic Drugs
For patients who have been seizure-free on established AED regimens, discontinuation of these medications in the last days of life is not recommended unless specifically directed by the patient's wishes or the clinical team determines that the burdens of continued treatment outweigh the benefits. Abrupt withdrawal of AEDs can precipitate withdrawal seizures, which are distressing and difficult to manage emergently.
Principles of Continuing AEDs
- Maintain existing AED doses where possible; do not reduce doses simply because the patient is dying.
- Switch to alternative routes when oral intake is no longer possible โ subcutaneous (SC), rectal (PR), buccal, or sublingual.
- If a CSCI (continuous subcutaneous infusion) line is already in situ (e.g., for syringe driver use with morphine or midazolam), AEDs can often be added or co-infused โ consult a palliative care pharmacist for compatibility data.
- Not all AEDs are suitable for subcutaneous administration; phenytoin, carbamazepine, and lamotrigine have poor SC compatibility. Alternatives should be discussed with the treating team.
- Where possible, simplify polypharmacy โ consider whether all AEDs are still necessary or whether monotherapy with a benzodiazepine or levetiracetam may suffice.
Route Conversion Guide
| AED | Oral Dose (Typical) | Alternative Route | SC/PR Equivalent | Notes |
|---|---|---|---|---|
| Sodium valproate | 500โ2000 mg/day PO | PR / SC (as valproic acid) | Equivalent total daily dose PR; SC at ~80% of oral dose | SC valproate available via some compounding pharmacies; discuss with pharmacist |
| Levetiracetam | 500โ3000 mg/day PO | SC (compatible with CSCI) | Same total daily dose SC; well tolerated subcutaneously | Increasingly preferred for SC use in palliative care; PBS General Benefit |
| Clonazepam | 0.5โ8 mg/day PO | SC (CSCI) / SL / PR | Same total daily dose SC or SL | Well suited to CSCI; see dedicated section below |
| Phenytoin | 200โ500 mg/day PO | IV (fosphenytoin) | Not suitable for SC; IV loading possible if access available | Consider substitution with levetiracetam or benzodiazepine if IV access unavailable |
| Phenobarbitone | 60โ200 mg/day PO | SC / IM / PR | Same total daily dose SC; well absorbed | Can cause significant sedation; useful for refractory seizures |
Acute Seizure Management
Acute seizures in the last days of life may present as generalised tonic-clonic activity, focal seizures, or subtle myoclonic jerking. Management depends on whether a seizure is a single, self-limiting event or part of a recurrent or prolonged pattern. The clinical goal is prompt symptom relief with the least invasive route appropriate to the setting.
Assessment
- Confirm the event is a seizure (not terminal myoclonus, which is common and does not require anticonvulsant treatment).
- Assess duration โ a seizure lasting >5 minutes in the palliative context should be treated as status epilepticus and managed urgently.
- Check for reversible precipitants if consistent with goals of care: hypoglycaemia, hyponatraemia, uraemia, medication toxicity (e.g., tramadol, meperidine), or infection.
- Review current AED regimen โ has it been inadvertently discontinued?
Stepwise Acute Management
Distinguishing Seizures from Terminal Myoclonus
| Feature | Seizure | Terminal Myoclonus |
|---|---|---|
| Duration | Seconds to minutes | Brief, repetitive jerks (seconds) |
| Pattern | Rhythmic, may be focal or generalised | Irregular, multifocal, often bilateral |
| Consciousness | Impaired or lost | Often already unresponsive |
| Associated features | Tongue biting, incontinence, post-ictal state | No post-ictal confusion; may be stimulus-sensitive |
| Treatment | Benzodiazepines, AEDs | Clonazepam 0.5โ1 mg SC/PO; reassurance; often does not require treatment if not distressing |
Clonazepam
Clonazepam is a long-acting benzodiazepine with potent anticonvulsant properties. It is widely used in palliative care for both acute seizure management and ongoing seizure prevention when given as a continuous subcutaneous infusion (CSCI). It is also effective for myoclonus and anxiety, making it a versatile agent in end-of-life symptom management.
Midazolam
Midazolam is a short-acting benzodiazepine and the first-line agent for acute seizure management in palliative care. Its rapid onset, suitability for subcutaneous administration, and short duration of action (when given as bolus) make it ideal for both acute seizure termination and, when given as a CSCI, for ongoing seizure prevention in the last days of life.
Midazolam vs Clonazepam โ Comparative Summary
| Feature | Midazolam | Clonazepam |
|---|---|---|
| Onset (SC) | 2โ5 minutes | 15โ30 minutes |
| Duration (bolus) | 15โ60 minutes | 6โ12 hours |
| Best role | Acute seizure termination; CSCI for status or recurrent seizures | Ongoing seizure prevention; adjunct to midazolam; myoclonus |
| SC tolerability | Excellent โ first-line for CSCI | Good โ well tolerated in CSCI |
| Sedation potential | High โ dose-dependent; more easily titratable due to short duration | Moderate to high โ accumulation risk with prolonged use |
| Typical CSCI dose | 30โ200 mg/24 h (higher for refractory status) | 0.5โ8 mg/24 h |
| PBS status | PBS General Benefit | PBS General Benefit |
Special Populations
Paediatrics
Midazolam: 0.1โ0.2 mg/kg SC/IM STAT; CSCI 0.05โ0.1 mg/kg/hr. Use weight-based dosing; neonates and infants require lower doses and close monitoring.
Clonazepam: 0.01โ0.03 mg/kg/day PO in 2โ3 divided doses; SC dosing should be guided by a paediatric palliative care specialist.
Paediatric palliative care is a highly specialised area. Refer to a paediatric palliative care service (e.g., Bear Cottage, Very Special Kids, or state-based services) for guidance on medication selection and dosing in neonates and children.
Pregnancy
Benzodiazepines: Category C. Avoid in pregnancy where possible, but in the palliative context the riskโbenefit equation differs โ seizure control is paramount for maternal comfort and safety.
Seizures in the last days of life during pregnancy is an extremely rare scenario. Obstetric and neonatal teams should be involved. Clonazepam and midazolam are both teratogenic in animal studies, but human data are limited. Individualised decision-making is essential.
Elderly
Benzodiazepines: Increased sensitivity to sedative effects; reduced hepatic clearance. Start at the lower end of the dose range for both midazolam and clonazepam.
Midazolam CSCI: Consider starting at 0.25โ0.5 mg/kg/24 h (rather than the standard 0.5โ1 mg/kg/24 h) in frail elderly patients.
Falls risk is irrelevant in the last days of life, but excessive sedation should be avoided if the patient has expressed a wish to remain alert. Review advance care plans and discuss sedation trade-offs with the patient and family.
Renal Impairment
Midazolam: Active metabolite (ฮฑ-hydroxymidazolam) accumulates in renal failure (eGFR <15 mL/min). Reduce dose by 25โ50% and monitor closely.
Clonazepam: Minimal renal excretion; generally no adjustment required, but monitor for excessive sedation.
Levetiracetam: Dose reduction required: 250โ500 mg BD if eGFR <50 mL/min; 250โ500 mg OD if eGFR <30 mL/min.
Uraemia itself may lower seizure threshold. In the last days, renal impairment is common and may be part of the dying process rather than a treatable condition โ align management with goals of care.
Hepatic Impairment
Midazolam: Half-life prolonged significantly in hepatic impairment (Child-Pugh B/C). Reduce dose by 30โ50%. Prefer shorter infusions with close monitoring.
Clonazepam: Hepatically metabolised; reduce dose. Avoid if possible in severe hepatic failure.
Levetiracetam: Renally cleared โ no hepatic adjustment required. Preferred AED in hepatic impairment.
Hepatic encephalopathy may itself cause seizures or myoclonus. Distinguish from true seizures and manage accordingly.
Immunocompromised
General: Seizures in immunocompromised patients may indicate CNS infection (toxoplasmosis, cryptococcal meningitis, progressive multifocal leukoencephalopathy), CNS lymphoma, or treatment-related neurotoxicity. If consistent with goals of care, investigate and treat reversible causes.
Drug interactions: Some AEDs (phenytoin, carbamazepine, phenobarbitone) induce CYP450 enzymes and may reduce levels of immunosuppressants (ciclosporin, tacrolimus). Levetiracetam and benzodiazepines do not have significant CYP interactions โ preferred in this population.
In the palliative context, the focus remains on comfort. If further investigation is not aligned with goals of care, empirical seizure management with benzodiazepines is appropriate.
Aboriginal and Torres Strait Islander Health Considerations
Aboriginal and Torres Strait Islander Australians experience a burden of disease approximately 2.3 times that of non-Indigenous Australians, with neurological conditions, cancers, and chronic kidney disease contributing significantly. End-of-life care for Indigenous Australians must be delivered in a culturally safe, family-centred, and community-connected manner. Palliative care access remains inequitable, particularly in remote and very remote communities.
๐ References
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