NUR 651 Advanced Pharmacology 1 Exam with 100%
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accurate detailed solutions || ||
Phenytoin (Dilantin) ||
Mechanism of action- Blocks posttetanic potentiation by stabilizing neuronal
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membranes. Decreases seizure activity by increasing the efflux or decreasing the influx
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of sodium ions across cell membranes in the motor cortex during generation of nerve
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impulse. It also regulates neuronal excitability by inhibiting calcium conduction
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through altering calcium uptake in presynaptic terminals and preventing cyclic
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nucleotide accumulation and cerebellar stimulation. || || || ||
Phenytoin (Dilantin) ||
Dosing- A loading dose is given. 15-20 mg/kg/day in both adults and children.
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Maximum infusion rate is 50 mg/min to avoid cardiovascular collapse. 25/mg/min in
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patients with preexisting cardiac disease. Oral dose is divided into three doses given
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every 2 to 4 hours to increase tolerability Max 400 mg/dose. Maintenance dose is 4 to
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6 mg/kg/day in adults and 5 to 12 mg/kg/day in children. based on age. Hold TF
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for1- 2 hours prior and 1-2 hours after dose.
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Phenytoin
Metabolized in a non-linear manner. As the amount of drug approaches a saturation
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point small incremental increases in a dose can result in disproportionately high
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serum levels. A therapeutic serum concentration is 10- 20 mcg/ml w normal albumin
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level. The therapeutic level of free unbound phenytoin is 1 to 2.5 mcg/Ml.
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, Phenytoin- contraindications ||
Carries a black box warning for cardiovascular events. Hypotension, and arrhythmias
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with rapid IV administration.
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Phenytoin adverse effects || ||
CNS effects
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gingival hyperplasia
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skin rash
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teratogenic
cardiovascular effects ||
phenytoin interactions Non-AEDs affecting phenytoin levels
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Drug:
Alcohol- long-term use = decreases phenytoin levels
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antacids, folic acid, rifampin, tube feedings
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Aspirin and diazoxide, tolbutamide- increases free phenytoin levels
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Increases total phenytoin levels
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Alcohol- shortly after intake, amiodarane, choramphenicol, chordizepoxide
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chlopheniramine, cimetidine, disulfiram, fluconazole, imipramine, isoniazid,
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metronidazole, omeprazole, propoxyphene, sulfonamides, ticlopidine, trazodone.
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|| || || || || || || ||
accurate detailed solutions || ||
Phenytoin (Dilantin) ||
Mechanism of action- Blocks posttetanic potentiation by stabilizing neuronal
|| || || || || || || || ||
membranes. Decreases seizure activity by increasing the efflux or decreasing the influx
|| || || || || || || || || || ||
of sodium ions across cell membranes in the motor cortex during generation of nerve
|| || || || || || || || || || || || || || ||
impulse. It also regulates neuronal excitability by inhibiting calcium conduction
|| || || || || || || || || ||
through altering calcium uptake in presynaptic terminals and preventing cyclic
|| || || || || || || || || ||
nucleotide accumulation and cerebellar stimulation. || || || ||
Phenytoin (Dilantin) ||
Dosing- A loading dose is given. 15-20 mg/kg/day in both adults and children.
|| || || || || || || || || || || || ||
Maximum infusion rate is 50 mg/min to avoid cardiovascular collapse. 25/mg/min in
|| || || || || || || || || || || ||
patients with preexisting cardiac disease. Oral dose is divided into three doses given
|| || || || || || || || || || || || ||
every 2 to 4 hours to increase tolerability Max 400 mg/dose. Maintenance dose is 4 to
|| || || || || || || || || || || || || || ||
6 mg/kg/day in adults and 5 to 12 mg/kg/day in children. based on age. Hold TF
|| || || || || || || || || || || || || || || || ||
for1- 2 hours prior and 1-2 hours after dose.
|| || || || || || || ||
Phenytoin
Metabolized in a non-linear manner. As the amount of drug approaches a saturation
|| || || || || || || || || || || || ||
point small incremental increases in a dose can result in disproportionately high
|| || || || || || || || || || || ||
serum levels. A therapeutic serum concentration is 10- 20 mcg/ml w normal albumin
|| || || || || || || || || || || || ||
level. The therapeutic level of free unbound phenytoin is 1 to 2.5 mcg/Ml.
|| || || || || || || || || || || ||
, Phenytoin- contraindications ||
Carries a black box warning for cardiovascular events. Hypotension, and arrhythmias
|| || || || || || || || || || ||
with rapid IV administration.
|| || ||
Phenytoin adverse effects || ||
CNS effects
||
gingival hyperplasia
||
skin rash
||
teratogenic
cardiovascular effects ||
phenytoin interactions Non-AEDs affecting phenytoin levels
|| || || || ||
Drug:
Alcohol- long-term use = decreases phenytoin levels
|| || || || || ||
antacids, folic acid, rifampin, tube feedings
|| || || || ||
Aspirin and diazoxide, tolbutamide- increases free phenytoin levels
|| || || || || || ||
Increases total phenytoin levels
|| || ||
Alcohol- shortly after intake, amiodarane, choramphenicol, chordizepoxide
|| || || || || || ||
chlopheniramine, cimetidine, disulfiram, fluconazole, imipramine, isoniazid,
|| || || || || ||
metronidazole, omeprazole, propoxyphene, sulfonamides, ticlopidine, trazodone.
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