Neurological Drugs Part 2 – Anti-Seizure Agents, Muscle Relaxants & CNS Stimulants

These flashcards review mechanisms, indications, contraindications, adverse effects, nursing considerations, and patient-education points for anti-seizure drugs, muscle relaxants, and CNS stimulants discussed in Neurological Drugs Part 2.

What is the primary therapeutic goal of anti-seizure pharmacotherapy?

To prevent or control most seizures by limiting neuronal firing and spread of impulses.

How do antiepileptic drugs (AEDs) differ from anticonvulsants in typical use?

AEDs are used for long-term seizure prevention/maintenance, whereas anticonvulsants are used to stop an active seizure; the distinction can be as simple as dose magnitude.

Approximately what percentage of clients can become seizure-free with optimal therapy?

About 70%.

Why is monotherapy preferred in seizure management when possible?

It reduces adverse effects, drug interactions, and simplifies monitoring while still achieving seizure control.

Name three electrolytes whose cellular movement is altered by most anti-seizure drugs.

Sodium (Na⁺), Potassium (K⁺), and Calcium (Ca²⁺).

List the three specific effects produced by the general mechanism of AEDs.

1) Raised seizure threshold in the motor cortex, 2) Suppressed transmission from one neuron to another, 3) Decreased speed of nerve impulse conduction.

Which five broad seizure types must be matched carefully with drug choice?

Focal, Secondary Generalised, Generalised Tonic-Clonic, Absence, and Myoclonic seizures.

What barbiturate and its pro-drug are first-line for status epilepticus?

Phenobarbital and its pro-drug primidone.

Describe the barbiturate mechanism of action relevant to seizures.

They enhance GABA activity in the reticular activating system, stabilising neuronal membranes and depressing impulse conduction to cortical and motor areas.

State two major adverse effects of barbiturates besides CNS depression.

Cardiac dysrhythmias and Stevens–Johnson Syndrome.

Why must primidone sometimes be chosen over phenobarbital?

Primidone provides anticonvulsant effects at lower phenobarbital serum levels, reducing toxicity (synergism).

Which hydantoin is gradually replacing phenytoin and why?

Fosphenytoin because it causes less soft-tissue irritation and sedation.

What is the primary cellular action of hydantoins such as phenytoin?

They regulate sodium influx/efflux in cortical neurons, preventing rapid repetitive depolarisation-repolarisation cycles.

Name two long-term adverse effects specific to phenytoin.

Gingival hyperplasia and hirsutism.

Why is low serum albumin a contraindication for phenytoin therapy?

Phenytoin is 90% protein-bound; low albumin increases free drug, raising toxicity risk.

Which benzodiazepine and route/dose are first-line in status epilepticus?

Lorazepam 4–8 mg IV.

How do benzodiazepines raise the seizure threshold?

They potentiate GABA at the reticular activating system and limbic system, leading to neuronal membrane stabilisation.

List two contraindications common to benzodiazepine use.

Pregnancy and narrow-angle glaucoma (also alcohol co-use).

Which iminostilbene is second most-prescribed for focal and tonic-clonic seizures?

Carbamazepine.

Why should carbamazepine be avoided in absence or myoclonic seizures?

It can worsen these seizure types.

What fruit must be avoided with carbamazepine and why?

Grapefruit; it inhibits CYP450 enzymes, raising carbamazepine levels and toxicity risk.

What drug class is first choice for absence seizures in paediatrics?

Succinimides – specifically ethosuximide.

Which anti-seizure drug increases brain GABA by blocking its re-uptake and is hepatotoxic?

Valproic acid (and its derivative divalproex).

Lamotrigine major caution when combined with valproic acid?

Increased risk of Stevens–Johnson Syndrome.

Gabapentin’s approved anti-seizure role and a common non-seizure use?

Adjunct for focal seizures; also widely used for neuropathic pain.

State two key patient-education points for all AEDs regarding lifestyle/safety.

Strict compliance with dosing & drug-level monitoring, and caution with hazardous activities such as driving due to possible sedation.

What nursing assessments are essential 1–3 weeks after initiating an AED?

Check for Stevens–Johnson Syndrome (rash, mucosal lesions) and monitor vitals, sedation, labs (CBC, liver, renal, sodium, and drug levels).

Which diluent and line filter are mandatory when giving IV phenytoin?

Normal saline (NS) with an in-line filter.

Which muscle relaxant directly acts on skeletal muscle?

Dantrolene.

How does baclofen relieve spasticity?

It is a GABA derivative that depresses nerve transmission at the spinal cord level.

Name two common CNS-depressant adverse signs to monitor with muscle relaxants.

Sedation and respiratory depression.

For CNS stimulants, what paradoxical effect occurs at low doses in ADHD?

They produce a calming, focusing effect rather than typical stimulation.

List three mechanisms by which amphetamines enhance NE and dopamine.

1) Increase their release, 2) Block their reuptake, 3) Inhibit MAO that metabolises catecholamines.

What is the usual paediatric starting dose of methylphenidate for ADHD (≥6 yrs)?

5 mg twice daily.

Provide two common adverse effects of therapeutic-dose methylphenidate.

Insomnia and decreased appetite/weight loss.

What serious psychological adverse event may CNS stimulants precipitate?

Increased suicidal thoughts or behaviours.

When should methylphenidate be taken to minimise insomnia?

In the morning, 30–45 minutes before breakfast (and early afternoon if BID).

Identify two vital parameters nurses must monitor regularly in children on ADHD stimulants.

Blood pressure and heart rate (also weight/appetite).

Which non-controlled drug used for narcolepsy promotes wakefulness with fewer SNS effects?

Modafinil (Alertec, Provigil).

Atomoxetine’s drug class and therapeutic use?

It is a norepinephrine reuptake inhibitor used for ADHD as a non-stimulant option.

Why is a comprehensive behavioural and social assessment required before starting ADHD pharmacotherapy?

To establish baseline function and rule out other causes, and to measure future therapeutic response or adverse behavioural changes.

What patient accessory is recommended for anyone on chronic anti-seizure therapy?

A Medic-Alert bracelet indicating epilepsy and current medications.

How can IV infusion of phenytoin cause tissue damage?

Extravasation may lead to local soft-tissue irritation and necrosis.

Which AEDs are contraindicated in pregnancy due to teratogenic risk?

Many, notably barbiturates, benzodiazepines, hydantoins, valproic acid, and carbamazepine.