Anti-epileptics Flashcards
MOA of Carbamazepine?
Inhibits neuronal sodium channels
This drug is used for seizure prophylaxis in epilepsy. Specifically, this drug is a second-line option for focal seizures (with or without secondary generalisation).
It can also be used for trigeminal neuralgia, and sometimes in mood disorders
Carbamazepine
Adverse effects of this drug include worsening of myoclonic and absence diplopia, ataxia, agranulocytosis, hepatic toxicity, SIADH (oedema and hyponatraemia) Stevens-Johnson syndrome- particularly in HLA B 1502
Carbamazepine
Carbamezepine warnings: exposure in utero is associated with NTD’s, cleft palate, cardiac and urinary tract abnormalities. Women planning a pregnancy should consider taking high dose _____ ______ supplements before conception.
folic acid
Use caution when prescribing Carbamazepine with drugs that induce metabolism by the CYP enzymes (eg Warfarin, oestrogens, erythromycin, lidocaine, etc), so the effect of these drugs will be ___________ when taken together with Carbamazepine
reduced
This first-generation anti-convulsant is a non-specific sodium channel blocker and targets almost all voltage-gated sodium channel subtypes. It binds to INACTIVATED sodium channels
Phenytoin
This first-generation antiseizure medication is not often prescribed anymore due to the incidence and severity of side effects. It may be used in patients who have had their epilepsy controlled with it for a long time, and it can also be used in status epilepticus.
Phenytoin
Side effects of this drug include gingival hyperplasia, hirsutism, acne, megaloblastic anaemia (inhibits folate absorption) S-J syndrome, and SLE-like syndrome
Phenytoin
These two core drugs are INDUCERS of CYP450 metabolism, so can make certain drugs less effective (impact can continue weeks after discontinuation)
Carbamazepine and phenytoin
This drug is 90% protein-bound, so only the free drug is active. Caution in administering this drug in conditions which alter protein such as liver failure, kidney failure, and pregnancy
Phenytoin
How do phenytoin and Carbamazepine affect the efficacy of hormonal forms of birth control?
It reduces the effectiveness of the birth control (reduces oestrogen levels)
How does oestrogen-containing birth control effect serum levels of valproate and lamotrigine?
It reduces the effectiveness of these drugs (ie oestrogen is epileptogenic)
Which two antiseizure medications should never be switched from brand name to generic versions?
Phenytoin and Carbamazepine
Which two antiseizure medications are liver enzyme inducers?
Phenytoin and Carbamazepine
What is the most common cause of seizure in a patient with a history of epilepsy?
Inconsistent use of anti-seizure medication
Focal seizures are typically due to loss of surrounding __________ (via GABAergic interneurons)
inhibition
Antiseizure medication such as valproate targets the T-type _______ channel, making it a helpful treatment for absence seizures
Calcium
Common side effects of most seizure medications include sedation, poor coordination, imbalance, fatigue, and osteopenia (if used long term). What are two of the more serious side effects associated with ASM’s?
Suicidal ideation and respiratory depression
Voltage gated sodium channel blockers are useful for what type of seizures?
Focal seizures
Indications for these two core drugs include epilepsy, trigeminal neuralgia, migraines, neuropathic pain, restless leg syndrome, anxiety/panic, and fibromyalgia
Gabapentin and pregabalin