Neurologic Drugs Flashcards by Caroline Miller

Name two changes in neurotransmitter levels that favor a reduction in seizure threshold

Excess glutamate (excitatory), deficiency of GABA (inhibitory)

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List risk factors for seizure (eight possible)

Trauma, surgery, electrolyte disturbances (hyponatremia), drug toxicity/withdrawal, stroke, infection, fever, genetics, idiopathic

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Which electrolyte disturbance causes the greatest risk for seizures?

Hyponatremia

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Describe goals of epilepsy treatment

Reduce seizure frequency, avoid medicine related adverse effects

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List two drug agents that have a wide spectrum effects against several types of seizure

VPA (valproic acid) and Lamotrigine

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How many antiepileptics do most patients take to control symptoms?

Most achieve control with monotherapy (one drug)

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When are drug levels in the blood checked?

Checked as trough right before dose

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Name an antiepileptic agent reserved for refractory generalized seizures due to highly sedating effects

Phenobarbital

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How are eclampsia seizures treated?

Magnesium sulfate

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Describe the use of BDZ’s and antiepileptics in seizure control

Benzos terminate seizures, antiepileptics are maintenance drugs

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List three drugs given to status epilepticus patients

Lorazepam (short half-life) diazepam (long half-life) fosphenytoin

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How does Phenytoin (Dilantin) work to treat seizures?

Promotes sodium efflux from neurons to stabilize cell and reduce hyperexcitability

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Name dose related adverse affects of phenytoin

Nystagmus (sign of toxicity) Headache, nausea, rash, confusion

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Name non-dose related adverse effects of phenytoin

Gingival hyperplasia, acne, coarsening of facial features

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Which two drugs studied so far cause gingival hyperplasia?

Phenytoin and nifedipine

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Name two interactions of phenytoin

Vitamin D (increases metabolism to cause osteomalacia), folate wasting

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Why is Fosphenytoin preferred to IV phenytoin?

IV phenytoin is unstable, must be combined with propylene glycol, and risks hypotension

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How often must fosphenytoin be taken and what is the therapeutic level?

TID or QID

10–20 mcg/mL

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When would a free phenytoin level test be ordered?

When hypoalbuminemia is suspected (drug is highly ppb)

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What pregnancy category is phenytoin and why?

Category D: Folate wasting causes neural tube defects

Define seizure

Excessive neuronal activity in cerebral cortex with disrupted or lost consciousness, possible confusion and hallucinations

How does valproic acid work to treat seizure?

Increases bioavailability of GABA, enhances activity of GABA, or mimics action of GABA at receptor sites

List three other indications of valproic acid

Migraines, bipolar disorder, agitation

What is the benefit of using valproic acid (rather than the usual benzo or narcotic) to treat agitation?

Valproic acid won’t cause respiratory depression

List adverse affects of valproic acid (six possible)

Hepatotoxicity, pancreatitis, thrombocytopenia, drowsiness, alopecia, weight gain

List some dosage forms of valproic acid

Sprinkle caps, tablets, capsules, delayed release, extended release, syrup, injection

What is the therapeutic level for valproic acid?

50-100 mcg/ml

What pregnancy category is valproic acid?

Category D

What type of drug is carbamazepine (Tegretol) related to?

TCA

How is the overdose of Tegretol and TCA treated?

Bicarb

How does carbamazepine work to treat seizures?

Reduces post synaptic transmission and response

Three other indications for carbamazepine?

Trigeminal neuralgia, bipolar, migraine prophylaxis

What is the therapeutic level of carbamazepine?

4 – 12 mcg/mL

List adverse affects of carbamazepine

Stevens Johnson syndrome, SIADH, hepatotoxicity

What is an autoinducer?

Revs up own metabolism over time causing increased dose requirements after several weeks

What is the analog of carbamazepine with fewer hepatic adverse effects called?

Oxycarbazepine (Trileptal)

What is the pregnancy category of carbamazepine and why?

Category D – causes folate wasting and spina bifida

What is gabapentin used for?

Neuropathy (in HIV, diabetics, spinal cord, slipped discs)

What is gabapentin the precursor to? How do these drugs differ?

Pregabalin (Lyrica): has greater addictive potential therefore C5 controlled substance

How is gabapentin eliminated?

Renally (extremely hydrophilic)

How does topiramate work to prevent seizures?

Block sodium channels, enhances GABA activity, weak carbonic anhydrase inhibitor

Name an off label use of topiramate

Weight loss

List adverse effects of topiramate

Anorexia, nephrolithiasis, psychomotor slowing (Topa makes you a dope-a)

What pregnancy category is Topiramate?

Category C

Which two antiepileptic drugs cause Stevens-Johnson syndrome?

Carbamazepine and Lamotrigine

List adverse affects of Levitracetam (keppra)

Somnolence (behavior changes)

Which two antiepileptics cause somnolence?

Levetiracetam (Keppra) and carbamazepine

List two cautions of all antiepileptics

Suicide risk (second generation) Avoid generic substitution

List the three first-generation AED's

Carbamazepine, phenytoin, valproic acid