BB2 Revision5 Flashcards
Which anti-epileptics should not be used in absence seizures, as they may exacerbate these types of seizures? [2]
Phenytoin
Carbamazepine
Explain the DDI effect that phenytoin and carbamazepine have on other drugs [3]
Phenytoin and carbamazepine:
* both induce metabolizing liver enzymes.
* These liver enzymes are involved of transformation of many drugs / increased metabolism
* which may result in the loss of efficacy of other drugs (other drugs may need an increase in dose as a response)
Explain what is meant by phenytoin’s dose dependent / zero order / saturation kinetics characteristics
Most drugs have first order elimination (rate of elimination is proportional to the plasma concentration).
However, with phenytoin, as the dose of drug is increased, because of saturated enzymes, the rate of elimination is no longer proportional to the concentration of drug in the plasma (i.e. there is saturation & so only a finite amount can be eliminated).
When this happens, small increases in drugs can cause large increases in plasma concentration
Antiepileptic drugs:
Name two calcium channels that are used as anti-epileptic drugs [2]
Ethosuximide
Gabapentin / pregabalin (in the PBL)
AEDs
What type of drug class does clonazepam belong to? [1]
State clonazepams MoA [1]
Benzodiazepines - GABA(A) receptor
positive allosteric modulators: enhance the frequency of GABA channel opening. (more GABA; causes more inhibition)
AEDs
What type of drug class does phenobarbitone and stiripentol belong to? [1]
What is MoA? [1]
phenobarbitone and stiripentol:
- Drug class: Barbiturates: GABAA receptor positive allosteric modulators
- . Phenobarbitone (leads to microsomal enzyme induction)
Enhances the duration of GABA channel opening. (more GABA; causes more inhibition
AEDs
Which drug inhibits GABA metabolism? [1]
Vigabatrin
Status elipeticus is a medical emergency. Name two drugs used to treat this conditon [2]
Lorezepam (IV)
Diazepam (IV)
Alternatives to AEDs
Name 3 surgical procedures that could be used to treat epilepsy [3]
Lobe resection
Corpus callasotomy (reduces propogation of seizures from one cerebral hemisphere to the next)
Functional hemispherectomy
Alternatives to AEDs
Name a type of diet that could help epilepsy [1]
Name a drug class for a potential new AED [1]
Keto diet
Cannabidiol
Which of the following type of channel does pregabalin target?
Ca2+
GABA
Na+
Glutamate
Which of the following type of channel does pregabalin target?
Ca2+
GABA
Na+
Glutamate
What is the MoA of Levetiracetam? [1]
Binds synaptic vesicle protein SV2A causing a reduction in conduction in neurones
SV2A protein is a part of secretory vesicle membranes that mediates calcium-dependent vesicular neurotransmitter release.
The binding of levetiracetam to SV2A appears to decrease the rate of vesicle release
Name a drug that predominately blocks Na+ channels, but also acts on Ca2+ channels and causes the presynaptic inhibition of glutamate release.
Lamotrigine
(hint: tri gated?)
AEDs
Focal Seizures Treatment:
First line: [] or []
Second line: [] or []
First line: carbamazepine or lamotrigine
Second line: sodium valproate or levetiracetam
Management of tonic-clonic seizures is with:
First line: []
Second line: [] or []
Management of tonic-clonic seizures is with:
First line: sodium valproate
Second line: lamotrigine or carbamazepine
Which drugs are used for absence seizures? [2]
ethosuximide, sodium valproate
Myoclonic seizures:
First line: [1]
Other options: [3]
First line: sodium valproate
Other options: lamotrigine, levetiracetam or topiramate
Describe the MoA of sodium channel active drugs like phenytoin and carbamazepine [1]
Stabilises Na+ channels inactivated state to decrease excitability
Explain MoA of Sodium valproate [3]
Potentiates GABA receptor;
Stops breakdown of GABA
Blocks voltage gated sodium channels and T-type calcium channels
State the veins from blue & red arrow [2]
Red arrow = vein of Trolard (superior anastomotic vein)
Blue arrow = vein of Labbe (inferior anastomotic vein)
What are the two types of strokes [2] & their causes [2]
Ischaemic (thrombotic; embolic): 80%
Haemorrhagic stroke (trauma; spontaneous): 20%
Name the leading causes of hemorrhagic stroke [5]
Major causes of hemorrhagic stroke
* Hypertension
* Aneurysm
* Elderly
* Head injury (trauma)
* Alcoholics
* Arteriovenous malformation