Neurology Drugs Flashcards
What is Levetricatem also known as?
Keppra
How does Leventricatem / Keppra work?
What is its half life?
What are its side effects?
Works by SV2A protein binding
HL = 7hr
AE = Neuropsychiatric
How does Valproate work?
What is its half life?
What are its side effects?
Na channel inhibition, GABA enhancement
HL = 12-15h
AE - Alopecia, tremor, thrombocytopenia, pancreatitis, fetal abnormalities
How does diazepam work?
What is its half life?
AEs?
Allosteric binding to GABA-A Receptor - increasing frequency in which Cl- channels open
HL = 30-40 hours
AE = respiratory depression, respiratory arrest, drowsiness, confusion, headache, syncope, nausea and vomiting, diarrhoea, and tremors.
How does carbamazepine work?
What is its half life?
What are its AEs?
Inhibits Na channels
HL= 12-18h
AEs = hyponatremia, leucopenia, aplastic anaemia, can have hypersensitivity
How does Phenytoin work?
What is its half life?
What are its AEs?
Inhibits Na channels
HL = 24h
AEs = gum hypertrophy, hirsutism, megaloblastic anaemia, cerebellar ataxia, atrophy and peripheral neuropathy
How many half lives does it take to reach steady state?
Approximately 5
What is steady state?
Where the rate of absorption = rate of elimination
What is a trough level with medications?
It is the lowest blood concentration of the drug - taken just before the next dose is given
Why is phenytoin a complex drug to give?
Is 90% protein bound - therefore alterations in proteins impact on the free (active) drug. Means there is a difference between individuals in terms of the level of saturation.
What things affect the available proteins for drug binding in the blood?
Liver failure
Kidney failure
Pregnancy
What metabolism considerations are there about Valproate?
Highly protein bound = will compete with phenytoin
Metabolised by liver, excreted in urine
Dose-dependant teratogenicity
What metabolism considerations are there about Carbamazepine?
Potent inducer of CYP450
Steady state not reached until 20 days due to auto induction. Is sub thereapeutic for 20 days because it incs liver metabolism = auto-induction.
When is a P considered to have drug-resistant epilepsy?
What are their tx options?
Considered drug-resistant if they have failed to respond to 2 different appropriate antiseizure meds
Options = surgery, neurostimulator devices, ketogenic diet
