Anticonvulsants Flashcards
Phenobarb is what class of med?
Barbituate
True/False: Phenobarb is usually effective in achieving complete seizure control
False, usually incomplete seizure control
Phenobarb is ___-line management for neonatal seizures
1st-line
What are the indications for use of Phenobarb?
- Neonatal seizures
- Generalized Tonic-clonic seizures
- Partial seizures
- Prolonged febrile convulsions
Newer agents such as _______ may develop a role in the mgmt of neonatal seizures as experience in their use is gained.
Keppra
What are the advantages of Phenobarbital use?
Wide spectrum of seizure activity Wide therapeutic range Availability IV & PO forms Low cost Extensive use in Pediatrics
What are the disadvantages of Phenobarbital use?
Respiratory depression Sedation Physical dependence Negative cognitive effects Hyperactivity Potential negative effects on developing neurons
What are the other conditions Phenobarbital may be used?
NAS
Cholestasis (enhances bile secretion)
How does Phenobarbital work?
potentiates inhibitory NT’s by prolonging the open state of GABA-mediated Na+ channels
True/False: Phenobarb has a large Vd?
True. It is distributed to all tissues, 50% bound to plasma protein
As GA increases, the Vd of Phenobarb _______.
Decreases
so as total body water decreases, the body fat increases
Do you give a loading dose of Phenobarbital?
Yes, 20 mg/kg IV
How often can additional doses be given after the load?
30-60 min for persistent seizures
What is the therapeutic level of Phenobarbital?
30-40 mcg/mL
True/False: effective seizure control has been r/t Phenobarb dose w/70% control in doses of 40 mg/kg
True
Infant’s requiring ECMO may need lower/higher doses of Phenobarbital to achieve effective serum concentrations.
Why?
Higher doses
Larger Vd
Serum concentrations of Phenobarbital 40-50 mcg/mL may produce what effects?
Levels >50 mcg/mL are a/w?
Levels >80 mcg/mL are a/w?
Respiratory depression
Coma
Bradycardia (too)
Respiratory depression & death
What is the T2 of Phenobarbital?
100-200 hours in a newborn
Phenobarb is metabolized where?
Excreted by?
Liver
Kidneys/in urine
Lorazepam (Ativan) is what type of drug?
Anticonvulant
When is Ativan used for seizures?
When they are refractory to conventional therapy
Lorazepam has dose-dependent _____ depression
CNS depression
Onset of action of Ativan is?
Peak concentration w/in?
Duration of action?
Mean T2 is?
5 minutes (quick!)
45 min
3-24 hrs
40 hrs
Can IV ativan be repeated?
yes, is given slow-push
What are the adverse effects of Ativan?
Respiratory depression
Rhythmic myoclonic jerking (preterm)
IV site-phlebitis/infiiltration
Monitor Renal fxn (excreted by kidneys)
Levetiracetam is also known as?
Keppra, LEV
Keppra is what type of medication?
Anticonvulsant
Is Keppra 1st or 2nd line tx for seizures?
2nd line refractory to Phenobarbital
Has Keppra been used as an alternative to Phenobarbital in neonates?
Yes
How does Keppra work?
Inhibits burst firing without affecting neuronal excitability
What are the therapeutic levels of Keppra?
Are levels usually run?
10-40 mcg/mL
No
What are the adverse effects of Keppra?
Are they common?
Minimal:
Somnolence, Fatigue, Ataxia, H/A, Behavioral changes
Phenytoin is also known as?
Dilantin
Phenytoin is an….?
Anticonvulsant
What are the indications of Phenytoin?
- Second-line therapy for managing neonatal seizures
- Status epilepticus
- Generalized tonic-clonic seizures
- Partial seizures with or without secondary generalization
Phenytoin continues to be used along with what other drug?
Phenobarbital
How does Phenytoin work?
- Blockade of voltage-sensitive Na+ channels–>inhibiting repetitive neuronal firing
- Alteration of Na+, K+, Ca++ conduction; membrane potentials; concentrations of AA’s; Norepinephrine, Acetylcholine; & GABA
If increase in Phenytoin is needed, how should it be done?
Why?
Small, incremental dose increases
As therapeutic serum concentrations are approached, the fraction of drug eliminated per unit of time decreases
How is Phenytoin metabolized?
Liver
Is Phenytoin given as a load + maintenance?
Yes, start w/load
True/False: the rate of infusion of Phenytoin is very important to prevent cardiac toxicity
True: bradyarrythmias & hypotension
Phenytoin is only compatible with?
NS
Is therapeutic monitoring of Phenytoin recommended?
Yes to minimize risk of toxicity
Are there many pharmacodynamic/pharmacokinetic interactions w/Phenytoin?
Yes, need to be considered very carefully
Is the therapeutic range for Phenytoin narrow or broad?
Narrow
