Miscellaneous Ant-epileptics Flashcards
What are the medicines that inhibit voltage gated Na+ channels ?
(CVPLT )
carbamazepine, valproic acid, phenytoin, lamotrigine, and topiramate,lacosamide,fosphenytoin.
What is the specific actions of Lamotrigine ?
selectively binds and inhibits voltage-gated sodium channels, stabilizing presynaptic neuronal membranes and inhibiting presynaptic glutamate and aspartate release.
What is the specific actions of Topiramate ?
*It inhibits Voltage gated Na+ and Voltage gated Ca2+ channels.
*It reduces membrane depolarization via AMPA/Kainate receptors and enhances GABA-A receptor activity, strengthening inhibitory effects.
*Topiramate inhibits the release of CGRP and glutamate from trigeminal neurovascular nerve endings, effectively disrupting cortical spreading depression in migraine.
What is the specific actions of Valproic acid ?
*It inhibits voltage gated Na+ and break down of GABA by inhibiting the enzyme GABA transamenase causing enhanced GABArgic transmission.
* It also enhances the Expression of the enzyme glutamic acid decarboxylase which converts glutamate to GABA.
* It effectively inhibits T-type calcium channels, which have been implicated in absence seizures and thalamocortical oscillations. It also enhances L-type calcium channels, which are involved in neuronal plasticity and neuroprotection. It also affect N-type calcium channels associated with neuropathic pain and migraine.
What are the commonly used medications for the treatment of GTCS ?
- Carbamazepine
- Phenytoin and Fosphenytoin
- Lamotrigine and Topiramate
- Valproic acid.
What are the Na+ blockers used for the Tx of absence seizures ?
Lamotrigine and Valproic acid.
What are the Na+ channel blockers of choice for the prophylaxis of status epilepticus ?
Phenytoin and Fosphenytoin.
What are the Na+ channel blockers used as mood stabilisers for bipolar disorder ?
Carbamazepine, Valproic acid, and lamotrigine.
Which is the Na+ channel blocker used as teh first line Tx of trigeminal neuralgia ?
Carbamazepine
What are the Na+ channel blockers used as prophylaxis for migraines and cluster headaches ?
Valproic acid and topiramate
What are the side effects of carbamazepine ?
- Diplopia and ataxia
- Agranulocytosis
- Liver toxicity
- SIADH
- Steven Johnson’s syndrome
What are the teratogenic effects of carbamazepine ?
Cleft palate and neural tube defects such as spina bifida.
What are the medications whose effects are reduced by the carbamazepine mediated induction of CYP450?
Benzodiapeines, Phenytoin, Quinidine, and Warfarin.
What are the common side effects of Lamotrigine ?
Bullered vision, Nausea, and vomiting.
What is the higher dose dependent side effect of lamotrigine ?
SJS
What are the main side effects of phenytoin ?
Nystagmus, diplopia, ataxia, hirsutism, and gingival hyperplasia.
How does phenytoin cause megaloblastic anaemia ?
By inhibiting folate absorption from the small intestine.
What are the rare side effects of Phenytoin ?
SJS and SLE like syndrome.
What are the teratogenic effects of phenytoin ?
IUGR, intellectual disability, cleft palate, and congenital heart defects.
What are the common side effects of valproic acid ?
GI symptoms, tremor, alopecia, weight gain, and thrombocytopenia.
What are the side effects of topiramate ?
Sedation, kidney stones, weight loss, and visual disturbances and glaucoma.
What are the calcium channel blockers used in neurologic diseases?
Ethosuximide, Gabapentin and levitracetam.
What is the drug of choice for absence seizures ?
Ethosuximide
What are the indications for calcium channel blocker Gabapentin?
Partial seizures, neuropathic pain, peripheral neuropathy, fibromyalgia and as a prophylaxis for migraine.
What is the MOA of Levitracetam ?
Its exact mechanism of anti-epileptic effect is unknown. However, it prevents calcium-dependent vesicular neurotransmitter release by selectively inhibiting synaptic vesicle protein 2A (SV2A).
What are the side effects of Ethosuximide ?
Itching, fatigue, GI symptoms, headache, and SJS.
What are the side effects of gabapentin ?
Sedation and ataxia.
What are the side effects of Levitracetam ?
Fatigue, sedation, headache, and changes in personality.
What is the MOA of Vigabatrin ?
It enhances GABArgic transmission by inhibiting the enzyme GABA transamenase.
What is the MOA of Tiagabine ?
It inhibits the GABA reuptake of GABA from the synapse leading to enhanced gabargic transmission.
What is the indication for Vigabatrin and Tiagabine ?
It is used to treat partial seizures.
What is the serious side effect of vigabatrin ?
Permanent bilateral visual loss.
