NUR 651 Advanced
Pharmacology 1
Comprehensive Questions with
Verified Answers Graded A+
Phenytoin (Dilantin) - Answer: 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) - Answer: 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 - Answer: 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 - Answer: Carries a black box warning for cardiovascular events.
Hypotension, and arrhythmias with rapid IV administration.
, Phenytoin adverse effects - Answer: CNS effects
gingival hyperplasia
skin rash
teratogenic
cardiovascular effects
phenytoin interactions Non-AEDs affecting phenytoin levels - Answer: 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.
Carbamazepine(Tegretol) Indications/ Uses - Answer: Treatment of partial and generalized tonic-
clonic seizures. First-line drug choice for monotherpay in simple or complex partial seizures with
secondary generalization.
Carbamazepine (Tegretol) MOA - Answer: Antiepileptic: inhibits Na channels
Carbamazepine dosing - Answer: 100-200 mg PO BID start, maintenance 800 to 1200 mg BID
divided into 2 to 4 doses. The therapeutic plasma concetration is 4 to 12 mg/L - Underogoes
autoinduction which begins 3 to 5 days into therapy and is complete after 21 to 28 days of
therapy.* serum concentrations will often vary significantly from 1 week to week 4 of therapy.
Frequent monitoring may be required following intiation or changes in doseing.
Pharmacology 1
Comprehensive Questions with
Verified Answers Graded A+
Phenytoin (Dilantin) - Answer: 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) - Answer: 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 - Answer: 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 - Answer: Carries a black box warning for cardiovascular events.
Hypotension, and arrhythmias with rapid IV administration.
, Phenytoin adverse effects - Answer: CNS effects
gingival hyperplasia
skin rash
teratogenic
cardiovascular effects
phenytoin interactions Non-AEDs affecting phenytoin levels - Answer: 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.
Carbamazepine(Tegretol) Indications/ Uses - Answer: Treatment of partial and generalized tonic-
clonic seizures. First-line drug choice for monotherpay in simple or complex partial seizures with
secondary generalization.
Carbamazepine (Tegretol) MOA - Answer: Antiepileptic: inhibits Na channels
Carbamazepine dosing - Answer: 100-200 mg PO BID start, maintenance 800 to 1200 mg BID
divided into 2 to 4 doses. The therapeutic plasma concetration is 4 to 12 mg/L - Underogoes
autoinduction which begins 3 to 5 days into therapy and is complete after 21 to 28 days of
therapy.* serum concentrations will often vary significantly from 1 week to week 4 of therapy.
Frequent monitoring may be required following intiation or changes in doseing.
