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All antiepileptic drugs should be withdrawn slowly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