Pharmacology for acute neuro and seizures Flashcards
What does mannitol do?
Mannitol reduces cerebral edema
It creates an osmotic force in the blood vessels, pulling fluid out of the brain into the blood
Brand name for mannitol
Osmitrol
Mannitol MOA
Increases osmotic pressure within glomerular filtrate, inhibiting reabsorption of water and electrolytes. Causes excretion of: water, sodium, potassium, chloride, calcium, phosphorus, magnesium, urea, and uric acid
Indication for mannitol
Renal failure, edema, increased intracranial pressure
Therapeutic effect of mannitol (Osmitrol)
Reduction of intracranial pressure. Urine output at least 30-50 cc/hr
How is mannitol (Osmitrol) administered?
Intravenously
Adverse effects of mannitol (Osmitrol)
Pulmonary edema
Electrolyte imbalances
Contraindications for mannitol (Osmitrol)
Hypersensitivity
Anuria
Dehydration
Pulmonary edema/ congestion
Nursing considerations for mannitol (Osmitrol)
Vital signs
Urine output
Signs and symptoms of dehydration
Signs and symptoms of fluid overload
Signs of electrolyte imbalance → confusion, anorexia, weakness, numbness, tingling, excessive thirst
Neurologic status → GSC, orientation
Monitor labs → electrolytes and kidney function (urea and creatinine)
Seizure MOA
Seizures involve a discharge from highly excitable neurone that spreads to other parts of the brain, thereby recruiting other neurons to discharge abnormally
Antiepileptic drugs aim to:
Suppress discharge of neurons
Suppress spread of seizure activity to other neurons
AED MOA
Suppress Na influx
Suppress Ca influx
Promote K efflux
Antagonize glutamate
Potentiate GABA
Patient education highlights for AED
Most antiepileptics require plasma drug level monitoring (helps to control seizures quickly)
Patient adherence - requires regular and continuous therapy
All antiepileptic drugs should be withdrawn slowly
Epilepsy and antiepileptic drugs carries a risk for depression in patients. All patients should be monitored for anxiety, agitation, depression, and suicidal ideation
Several antiepileptic drugs decrease the effectiveness of birth control pills
Teratogenic
Example of an osmotic diuretic
Mannitol (Osmitrol)
Description of hydantoin
Metabolized by liver
Narrow therapeutic window
Small changes in dosing can result in large changes to plasma levels
Small increases in hydantoin dose can lead to
toxicity
Small decreases in hydantoin dose can lead to
subtherapeutic levels
Brand name of phenytoin
Dilantin
Example of hydantoin
phenytoin (Dilantin)
Phenytoin (Dilantin) MOA
Inhibition of sodium channels, delays sodium channels from becoming active
Indication for phenytoin (Dilantin)
All types of seizures except absence seizures
Popular choice for tonic-clonic seizures
Therapeutic effect of phenytoin (Dilantin)
Diminished seizure activity
Protein binding info of phenytoin (Dilantin)
Dilantin is highly protein bound
Patients with low serum albumin levels will have increased effects of Dilantin
There are more freely unbound active drug present in their body
These patients require lower drug levels of Dilantin
Precautions and contraindications for phenytoin (Dilantin)
Hypersensitivity
Sinus bradycardia, heart block (2nd and 3rd degree)
Teratogenic
Use cautiously with depression and suicidal ideation
Use cautiously with renal, liver, cardiac disease
Adverse effects of phenytoin (Dilantin)
Suicidal thoughts
Nystagmus, drowsiness, ataxia, diplopia, cognitive impairment
Rash
Increase blood sugar (rare)
Hypotension, cardiac dysrhythmias (IV)
Gingival hyperplasia
Thrombocytopenia
Nursing considerations and assessment for phenytoin (Dilantin)
Monitor mental status closely → suicidal thoughts and changes in behaviour
Assess mouth and gums
Assess for rash (check for hypersensitivity) → usually within 2 wks of therapy
Assess for seizure activity, pt may be monitored with EEG
Monitor BP, pulse. ECG heart rhythms when IV
Monitor labs → albumin, CBC, calcium, liver enzymes, phenytoin levels during treatment, blood sugar
Patient education for phenytoin (Dilantin)
Avoid alcohol and CNS depressants because will cause extreme drowsiness
Do not skip doses
Have med alert bracelet
Diabetic patients should monitor blood sugars
Nursing care for phenytoin (Dilantin)
Implement seizure precautions
For pts with tube feed → stop feed 2hrs before and 2hrs after PO admin
IV phenytoin → never mix w/ dextrose ONLY normal saline
Monitor IV site closely → purple glove syndrome
Use special tubing w/ a filter
Admin IV slowly
Drug example for benzodiazepine
Lorazepam (Ativan)
Lorazepam (Ativan) MOA
Potentiated GABA
Indication for lorazepam (Ativan)
Anxity disorders
Insomnia
Seizures
Therapeutic effect of lorazepam (Ativan)
Decreased seizures
Additional info for lorazepam (Ativan)
Seizure rescue med - excellent for status epilepticus
Adverse effects of lorazepam (Ativan)
Apnea, respiratory depression
Bradycardia, hypotension
Drowsiness, lethargy, dizziness
Can lead to physical dependence
Precautions/ contraindications for lorazepam (Ativan)
Hypersensitivity
Patients with pre-existing CNS depression
Severe hypotension
Sleep apnea
Pregnancy
Nursing considerations for lorazepam (Ativan)
Antidote → Flumazenil, but if given to someone with seizures then could induce a seizures
Do not take with other CNS depressants or alcohol, do not drive or engage in activities requiring alertness
Assess levels of consciousness, vitals, respiratory status
Drug example of barbiturates
Phenobarbital (Ancalixir)
Phenobarbital (Ancalixir) MOA
Produces all levels of CNS depression. Inhibits impulse transmission in the CNS and raises seizure threshold. Binds to GABA receptors, causing the receptors to respond more intensely to GABA
Indication for phenobarbital (Ancalixir)
Seizures
Sedation
Therapeutic effect of phenobarbital (Ancalixir)
Anticonvulsant activity
Additional info of phenobarbital (Ancalixir)
Takes 2-3 weeks for plasma levels to reach a steady therapeutic state, therefore loading doses are often given to increase serum levels
Precautions/ contraindications for phenobarbital (Ancalixir)
Hypersensitivity
Pre-existing CNS depression
Respiratory disease
Use cautiously in: liver disease, renal impairment, history of suicide attempts/ depression, history of drug abuse
Use in pregnancy will cause dependence in fetus
Teratogenic
Adverse effects of phenobarbital (Ancalixir)
Drowsiness
Respiratory depression
Bronchospasm
Physical dependence and addiction
Hypotension when given IV
Thrombocytopenia
Nursing considerations and assessment for phenobarbital (Ancalixir)
Monitor respiratory status, pulse, BP
Monitor pt carefully if hx of depression, suicidal ideation, or drug dependence
Assess for level of consciousness
Assess seizure activity
Labs → hepatic and renal function blood work, CBC, phenobarbital serum levels
Institute seizure and fall precautions
Doses should be decreased gradually
Patient education for phenobarbital (Ancalixir)
Do not abruptly stop
Do not skip doses
Do not take with other CNS depressants or alcohol
Drug family of carbamazepine (Tegretol)
Anticonvulsant
Carbamazepine (Tegretol) MOA
Decreases synaptic transmission in the CNS by affecting sodium channels in neurons
Indication for carbamazepine (Tegretol)
Most seizure types, not absence seizures
Therapeutic effect of carbamazepine (Tegretol)
Prevention of seizures
Additional info for carbamazepine (Tegretol)
Preferred drug because it has less adverse effects than others
Minimal effects on cognitive function
Precautions/ contraindications for carbamazepine (Tegretol)
Hypersensitivity
Bone marrow suppression (on chemo)
Use cautiously in: pregnancy, depression/ suicidal, liver disease, renal impairment, heart disease
Adverse effects of carbamazepine (Tegretol)
Neurologic effects → nystagmus blurred vision, diplopia, ataxia, more common in beginning then decreases (minimized with low dose)
Bone marrow suppression → cause neutropenia, anemia, and thrombocytopenia (rare; improves after discontinuation)
Teratogenic
Water retention → secretion of antidiuretic hormone
Nursing consideration and assessment for carbamazepine (Tegretol)
Monitor mental status
Assess seizure activity
Monitor CBC → platelets, RBC, WBC, d/c if signs of bone marrow suppression
Liver function tests and renal lab work, carbamazepine serum levels
Avoid grapefruit juice → can inhibit drug metabolism and increase peak levels of drugs
Valproic acid (Depakene) drug family
Anticonvulsant
Valproic acid (Depakene) MOA
Suppresses neuronal firing by blocking sodium channels
Suppresses calcium influx
Increases levels of GABA
Indication for valproic acid (Depakene)
Treats all major seizure types
Bipolar disorder
Migraine headaches
Therapeutic effect of valproic acid (Depakene)
Suppression of seizure activity
Additional info for valproic acid (Depakene)
Generally well tolerated
Contraindicatins/ precautions for valproic acid (Depakene)
Hypersensitivity
Liver and renal impairment
Use cautiously in patients with bleeding disorders and bone marrow suppression
Use cautiously in patients with depression and suicidal thoughts
Teratogenic
Adverse effects of valproic acid (Depakene)
Gastrointestinal effects → nausea/ vomiting, indigestion, take w/ food to minimize symptoms
Hepatotoxic
Pancreatitis
Highly teratogenic, especially in first trimester
Nursing considerations and assessment for valproic acid (Depakene)
Assess for seizure activity
Assess mental status, behaviour changes
Monitor CBC (platelets, WBC, RBC)
Monitor liver function tests, monitor serum drug levels
Patient education for valproic acid (Depakene)
Med alert bracelet
Do not skip doses
Take as ordered
Do not drive or engage in activities requiring alertness
Drug family of gabapentin (Neurontin)
Anticonvulsant
MOA of gabapentin (Neurontin)
Exact MOA unknown
Thought to increase GABA release
Indication for gabapentin (Neurontin)
Neuropathic pain
Migraines
Partial seizures (Adjunctive therapy for seizures)
Therapeutic effect of gabapentin (Neurontin)
Decreased incidence of seizures
Precautions and contraindications for gabapentin (Neurontin)
Hypersensitivity
Use cautiously in patients with depression and suicidal thoughts
Use cautiously with renal disease
Adverse effects of gabapentin (Neurontin)
Mild to mod side effects - drowsiness and dizziness
Considered a very safe med
Elderly patients eliminate the drug slowly and more susceptible to side effects → greater fall risk
Does not interact with other meds
Nursing considerations and assessments for gabapentin (Neurontin)
Monitor mental status - assess for depression and suicidal thoughts
Assess seizure activity
Drug family of levetiracetam (Keppra)
Anticonvulsant
Levetiracetam (Keppra) MOA
unknown
Indication for levetiracetam (Keppra)
All types of seizures (adjunct for partial seizures and generalized seizures)
Migraines
Bipolar disorder
Therapeutic effect of levetiracetam (Keppra)
Decreased seizure activity
Contraindications and precautions for levetiracetam (Keppra)
Hypersensitivity
Use cautiously in renal impairment
Could pose risk to fetus, should not be taken while breastfeeding
Adverse effects of levetiracetam (Keppra)
Renal injury
Side effects generally mild otherwise
Does not affect cognition, concentration, or speech
Drowsiness and weakness
Very rare → agitation, anxiety, depression, psychosis, hallucinations
Nursing considerations and assessments for levetiracetam (Keppra)
Assess seizure activity
Assess for weakness and drowsiness
Assess for behavioural changes, emotional lability during first 4 wks of therapy
Advise pt to notify if changes in thought processes
Drug family of topiramate (Topamax)
Anticonvulsant
Topiramate (Topamax) MOA
Potentiates GABA
Blockage of sodium channels
Blockage of calcium channels
Blockage of glutamate receptors
Indication for topiramate (Topamax)
Adjunctive therapy for partial and generalized seizures
Bipolar disorder
Headaches
Eating disorders
Therapeutic effect of topiramate (Topamax)
Decreased incidence of seizures
Contraindications and precautions of topiramate (Topamax)
Hypersensitivity
In patients who regularly drink alcohol
Breastfeeding, teratogenic
Use cautiously in patients with depression and suicidal thoughts, liver and renal impairment, dehydration
Important info for topiramate (Topamax)
NO alcohol use within 6 hrs before and 6 hrs after taking meds
Adverse effects of topiramate (Topamax)
Drowsiness, dizziness
Weight loss, anorexia
Metabolic acidoses → increases renal excretion of bicarb, causing pH to decrease, leading to hyperventilation to compensate
Suicide ideation - higher risk
Anemia
Decreased sweating → hyperthermia
Nursing considerations and assessment for topiramate (Topamax)
Monitor for changes in behaviour and mood
Assess seizure activity
Monitor labs → CBC, liver enzymes, serum bicarb
Advice against driving or activities requiring alertness
Change positions slowly
No alcohol with this med
May affect hormonal contraceptive effectiveness
