Week 10 - Migraine/Neurologic Flashcards
What is the difference between the Phenytoin (Dilantin) blood level and free phenytoin blood levels?
Blood level = bound + unbound
Free = unbound
Because phenytoin is very highly protein bound with a narrow therapeutic range, if the patient has low albumin, they can experience symptoms of toxicity even if their total phenytoin result falls within therapeutic range
Phenytoin (Dilantin) Class: Mechanism: Uses: Contraindication:
Class: Anticonvulsant, Hydantoin
Mechanism: Suppresses abnormal neuron firing by suppressing the sodium influx – returns nerve cells to a stable resting potential and limits excitability
Uses: Seizure treatment/prophylaxis
Contraindication: Pregnancy (teratogen!) - monitor serum levels closely in pregnancy as seizures become more frequent due to increased metabolic rates
Phenytoin (Dilantin)
Serum level:
Side/Adverse Effects (13):
Serum level: 10-20 mcg/mL
Effects: gingivitis, gingival hyperplasia, nystagmus, diplopia, H/A, dizziness, slurred speech, decreased coordination, alopecia, Thrombocytopenia, Steven Johnson, hypotension, liver toxicity
Phenytoin (Dilantin) Drug Interactions:
-With Cimetidine (Tagamet), Isoniazid, Sulfonamides
Increased effects WITH Cimetidine (Tagamet), Isoniazid, Sulfonamides)
Phenytoin (Dilantin) Drug Interactions:
-With folic acid, antacids, calcium, sucralafate, antineoplastics, antipsychotics, primrose, gingko
Decreased effects with folic acid, antacids, calcium sucralafate, antineoplastics, antipsychotics, primrose, gingko
Primrose effect on Phenytoin
Lowers seizure threshold
Gingko effect on Phenytoin
Decreases phenytoin effectiveness
Phenytoin (Dilantin) Drug Interactions
–Anticoagulants, oral contraceptives
Decreased effects OF anticoagulants, oral contraceptives, antihistamines, dopamine, theophyline
Phenytoin effect on heart
Has anti-arhythmic properties
Phenytoin effect on Insulin
Inhibits insulin release – increases glucose level
Phenytoin (Dilantin) Nursing Interventions
- Shake suspension well for 5 min
- Monitor serum levels
- Safety
- Warn females taking oral contraceptives to use additional contraception
- Avoid herbs, alcohol, and CNS depressants
- Don’t stop abruptly
- Frequent oral hygiene and checkups (r/t gingivitis, gingival hyperplasia)
- Monitor glucose levels in diabetics (can increase glucose)
- Report sore throat, bruising, nose bleeds
- Medical alert ID
What can you mix Dilantin IV with?
ONLY normal saline
Migraines
Unilateral or bilateral steady throbbing head pain + photophobia + N/V
Symptoms of Migraine (4)
- Persist for 4-24 days, or multiple days
- Triggered by food, hormones, stress, meds, fatigue
- decreased or asymptomatic in pregnancy and menopause
- aura and prodromal symptoms
Classic migraine
aura
Common migraine
no aura
Drug treatment for MILD migraine
Analgesics - Aspirin, Tylenol, Ibuprofen
- ASA alone or with caffeine (potentiates effect)
- Chronic daily dosing of Tylenol can cause liver damage so watch out
Drug treatment for MODERATE TO SEVERE migraine
Selective Serotonin (5-HT) Receptor Agonists (Triptans)
Sumatriptan (Imitrex) Class: Mechanism: Use: Routes (3):
Class: Selective Serotonin (5-HT) Receptor Agonist
Mechanism: Binds to selective serotonin receptor sites to cause VASOCONSTRICTION of cranial vessels
Use: Acute migraine treatment
Routes (3): PO, SC, nasal spray
Sumatriptan (Imitrex)
Contraindications (2):
Side effects (8):
Adverse (12):
Contraindications (2): CAD, vascular disease (b/c it vasoconstricts) Side effects (8): Dizziness, tingling, warm sensations, numbness, drowsiness, cramps, N/V diarrhea Adverse (12): HTN, hypotension, heart block, angina, dysrhythmia, thromboembolism, seizures, CNS hemorrhage, stroke, coronary vasospasm, MI, cardiac arrest
Carbidopa-Levodopa (Sinemet)
Class:
Mechanism:
Uses:
Class: Dopaminergic (restores dopaminergic levels)
Mechanism: Carbidopa inhibits dopa decarboxylase to reduce metabolism of levodopa, increase amount of levodopa available for dopamine conversion, and reduce the amount of levodopa needed
Uses: Parkinsons
Carbidopa-Levodopa (Sinemet) Side Effects (10):
- Fatigue, insomnia
- Dyskinesia, orthostatic hypotension
- Dry mouth, blurred vision, urinary retention
- N/V, dysrhythmia, palpitations
Groups of drugs used in Alzheimer’s
ACh inhibitors and N-Methyl-D-asparate Inhibitor (NMDA)
ACh inhibitors for AZ Mechanism: Side effects (12):
Mechanism: blocks acetylcholinisterase to increase Ach levels (Cholinergic agonist)
Side Effects: H/A, dizziness, depression, GI distress, dehydration, dry mouth, constipation, blurred vision, insomnia, hyper/hypotension, dysrhythmia, hepatotoxicity
N-Methyl-D-Aspartate Inhibitor (NMDA) for AZ
Mechanism
Block NMDA receptors (which overstimulation of causes neurodegeneration) to reduce crate of clinical deterioration in patients with AZ
Methylphenidate (Ritalin) Class: Mechanism: Uses (3): Interactions (3):
Class: Amphetamine-like
Mechanism: Acts on cerebral cortex and reticular activity system to stimulate RAS/AROUSAL
Uses (3): ADHD, fatigue, narcolepsy, behavioral syndromes
Interactions (3):
-increased effects with caffeine
-decreased with decongestants, antihypertensives, barbituates
-may alter insulin effects
Methylphenidate (Ritalin) Side effects (17):
- Tachycardia, palpitations, HTN, dizziness
- sleeplessness, restlessness, nervousness, tremors, irritability, blurred vision
- Rash
- Increased hyperactivity
- Anorexia, dry mouth, vomiting, diarrhea, weight loss
- Thrombocytopenia
Methylphenidate (Ritalin)
Caution and interventions
- Risk for physical and psychological dependence
- Avoid concomitant use of MAO inhibitors (increased risk of toxicity)
- Give before breakfast and lunch, before 6pm
- Monitor CBC
- Avoid caffeine, alcohol
- Record height, weight, and growth of children
- Relieve dry mouth with sugarless gum
- Taper (don’t stop abruptly to avoid withdrawal)
Phenytoin PB
Free Dilantin range
85-95%
Free dilantin range: 1.0-2.0 mcg/mL
Too low dilantin symptom
Too low - seizure
