* Stroke & Epilepsy Pharm

Question 1

What is tissue plasminogen activators (tPA)?

Answer 1

• Clot busters
• Binds to fibrin to convert plasminogen to plasmin -> stimulates fibrinolysis of atherosclerotic lesion
• eg ALTEPLASE

Question 2

What is the inclusion criteria for tPA?

Answer 2

• > 18yo
• Last known well time is <4.5 hrs
• Ischemic stroke
  ~ with NIHSS >4

Question 3

What is the exclusion criteria for tPA?

Answer 3

• Evidence of hemorrhagic stroke (ICH/SAH)
• Active internal bleeding
• Stroke or head injury within past 3 months
• Intracranial or intraspinal surgery within the last 3 months
• While on warfarin, INR is >1.5, or PT > 15
• Received heparin within 48 hours + aPTT elevated
• Persistent blood pressure elevation
  ~ SBP > 185 or DBP > 100
• CBG <2.7 or >22.2 mmol/l

Question 4

What are the complications of tPA?

Answer 4

• Intracranial hemorrhage
• Other bleeding complications
• Angioedema
• Transient hypotension

Note: Tf need to monitor BP every 15 mins during tPA infusion

Question 5

Nursing PEARLs for tPA administration?

Answer 5

• Actual weight of px (for accurate dosing)
• 18-gauge IV access for perfusion imaging
  ~ + 2nd IV if px is receiving thrombolytics / receiving radiology for thrombectomy
• IV Alteplase must be swirled, NO shaking
• IV alteplase double-checked with 2nd clinician
• Check BP and neurological status 15 min before administration
  ~ BP prior: <185/110
  ~ BP after: <180/105 for 24 hrs
  ~ BP after (for px wo thrombolytics): <220/110 (permissive BP)

Question 6

What does antiplatelet and anticoagulant therapy include?

Answer 6

• Anti-PLT: Aspirin, Clopidogrel
• Anti-coag: Warfarin
  ~ INR 2-3
  ~ Used short term (3 mths) + followed by an anti-PLT
• Heparin anticoagulation

Question 7

What drug is used as a vasodilator to prevent vasospasms post-op for hemorrhagic stroke?

Answer 7

NIMODIPINE

Question 8

IMPT

What characteristics put a px at lower risk of recurrent seizures?

Answer 8

• Single seizure
• Normal EEG
• Normal brain scan

Question 9

IMPT

What puts a px at higher risk of recurrent seizures?

Answer 9

• Previous undiagnosed seizures
• Epileptiform seizures (whack EEGs)
• Abnormal brain scans

Question 10

What are the main anti-epileptic drugs?

Answer 10

• Phenytoin
• Carbamazepin
• Valproate
• Benzodiazepine (drug class)

Pls Control Bellowing Voices

Question 11

IMPT:
What are the 2 main actions of anti-epileptics?

Answer 11

1) Decrease membrane excitability
- By altering Na and Ca2 conductance during action potentials

2) Enhance effects of inhibitory GABA transmitters

Question 12

IMPT:
How does phenytoin work and what is it used for?

Answer 12

• Blocks voltage-dependent Na+ channels
  ~ Decreases excitability of neurons

Suitable for all types of seizures
- Except absence seizures

Question 13

IMPT:
What precautions are there when using phenytoin?

Answer 13

1) Narrow therapeutic range
- 40-100 microM
- Careful titration needed

2) Non-linear r/s b/w dose and plasma concentration
- Requires titration and monitoring

3) Teratogenic
- Leads to birth defects
- Contraindicated in pregnancy

Question 14

IMPT:
- How does carbamazepine work and what is it used for?

Answer 14

• Similar to phenytoin (blockage of Na channels)

Suitable for all types of seizures
- Except absence seizures

Question 15

IMPT:
What precautions are there when using carbamazepine?

Answer 15

1) Repeated doses of carbamazepine induces increased production of CYP450 (hepatic enzyme)
- Accelerates elimination of drugs
- Half life of cbmzp + other drugs half-life shortens -> Drug dose needs to increase

2) May cause aplastic anemia
- Inability of bone marrow to produce all types of blood cells

Question 16

IMPT:

How does valproate work and what is it used for?

Answer 16

1) Blocks Na+ and Ca2+ channels
2) Inhibits GABA transaminase (which breaks down GABA) -> inc GABA in synaptic space
- Increases inhibition of excitatory action

Suitable for all types of seizures + absence seizures

Note: GABA maintains inhibitory tone that counterbalances neuronal excitation

Question 17

IMPT:

What are the precautions before using valproate?

Answer 17

1) Strongly binds to plasma proteins
- Displaces other antiepileptics -> needs to increase dose of those drugs
- Difficult for px on multi-therapy

Question 18

IMPT:
How do benzodiazepines work and what are they used for?

Answer 18

1) Enhances binding of GABA neurotransmitters on Cl- channels
- Increases inhibitory effect on excitatory neuron action
- Done by potentiating influx of Cl- ions leading to hyperpolarisation (opp of depolarisation)

Used when other antiepileptics are not effective

Question 19

IMPT

What are the more common benzodiazepines used to treat epilepsy?

Answer 19

Short-acting BZP not often used as multiple doses are required
- Unsafe due to addictive nature, w epilepsy being a chronic condition
- Effective duration only 3-8 hours

Intermediate-acting:
- CLONAZEPAM
- LORAZEPAM
- Used in refractory seizures (not effectively treated by first-line meds)
- Lorazepam also can be used for Status Epilepticus
- 10-20 hours

Long-acting:
- DIAZEPAM
- Used in refractory seizures and Status epilepticus
- 1-3 days effective duration

Question 20

IMPT:

When are anti-epileptic drug levels tested?

Answer 20

• When assessing COMPLIANCE of drug treatment of px w refractory epilepsy
• When suspecting possible anti-epileptic drug toxicity
• Titration of phenytoin dose due to therapeutic dose

Not required without clear clinical indication

Question 21

What are the 3 drugs used for insomnia?

Answer 21

• Triazolam
• Temazepam
• Flurazepam