Flashcards in Neuro exams - Parkinson's, Epilepsy and Glaucomo Deck (35)
What is the pathophysiology of parkinson's disease?
o Loss of Dopaminergic Neurones from the pars compacta of the Substantia Nigra in the midbrain that project to the striatum of the basal ganglia.
GIve main treatment for Parkinson's and five adjuvants
o Dopamine receptor agonists
o MAOI Type B inhibitors
o COMT inhibitors
When is L-dopa used?
Immediate precursor of dopamine and is able to penetrate the BBB to replenish the dopamine lost in the neostriatum
Give four of the main ADRs of L-dopa
Nausea and vomiting
Hallucinations, delusions (schizophrenia)
Cardiovascular effects (hypotension)
What does L-dopa have to be given with in order to prevent its breakdown?
Periperhal DOPA dexcarboxylase inhibitor
What kind of drugs can cause parkinson's like symptoms?
Why do you need to give a large dose of L-dopa?
Large amount of peripheral breakdown
What is the mechanism of dopamine receptor agonists?
Agonist for D2 receptors
What are some ADRs for dopamine receptor agonists?
Sedation, hallucination, confusion
What do monoamine oxidase type B inhibitors do?
selectively inhibits the MAOB enzyme in the brain that is normally responsible for the breakdown of dopamine. By inhibiting breakdown, the dose of L-DOPA is prolonged.
What are three ADRs for MAOIs
What do COMT I inhibitors do?
Inhibits the enzyme COMT, which degrades L-dopa in the periphery. No therapeutic effect alone.
Potentiates effects of L-dopa
Give three ADRs of COMT
Nausea and Vomiting
How do anti-cholinergics work in parkinsons?
Antagonists at the muscarinic receptors that mediate striatal cholinergic excitation
Acetylcholine -> Antagonistic effect on dopamine
Main action in treatment of Parkinson’s disease is to reduce excessive striatal cholinergic activity
Give two ADRs of anti-cholinergics
CNS effects – Mild memory loss, acute confusional states
Dry mouth and blurred vision (less common)
What does amantadine do?
Stimulates neuronal dopamine release and inhibition of its reuptake
Additional muscarinic blocking actions
Give three ADRs of amantadine?
What is the treatment in myasthenia gravis?
CRANIAL NERVES What do acetylcholinesterase inhibitors do?
Prevent breakdown of Ach in synaptic cleft
What is the major ADR of acetylcholinesterase inhibitors
What is another treatment for myasthenia gravis?
Removes AchR antibodies and gives short term improvement
What drug should not be given in Myasthenia gravis?
- Myasthenic crisis
- Cholinergic crisis
What is SSLUDGE syndrome?
What is the mechanism of action for lamotrigine?
Prolongs VGSC inactivation state
Give some DDIs for lamotrigine
Adjunct therapy with other anti-epileptic drugs
Oral Contraceptives reduce Lamotrigine plasma levels
Valproate increases Lamotrigine plasma levels (protein binding)
Give some ADRs for lamotrigine
Dizziness, ataxia, drowsiness
What is the mechanism of action of sodium valproate?
Weak inhibition of GABA inactivation enzymes GABAA
Weak stimulus of GABA synthesising enzymes GABA A
Weak VGSC blocker and Weak Ca2+ channel blocker Discharge
Give three ADRs for sodium valproate
Ataxia, tremor, weight gain
What is a big DDI for sodium valproate?
Displaces other AED (lamotrigine and phenytoin), increasing concentration
When is carbamezapine used?
Status epilepticus/second line in others
What is mech of action of carbamezapine?
Voltage gated sodium channel blocker
Give a couple of adverse drug reactions of carbamezapine?
What is the major cause of DDIs in carbamezapine treatment?
CYP450 Enzyme inducer
Why should phenytoin dose be carefully monitered?
Non-linear, can reach toxic doses quickly