Neuropharmacology

Question 1

What is the role of anti-epileptic drugs?

Answer 1

suppression of symptoms
not curative
may not affect disease progression

Question 2

MOA of carbamazepine, lamotrigine and phenytoin as anti-epileptics

Answer 2

inhibition of action potential
stabilise sodium ion channels
reduce high frequency discharge

Question 3

MOA of benzodiazepine and valproate as anti-epileptics

Answer 3

enhance GABA (inhibitory) transmission

Question 4

MOA of lamotrigine as an anti-epileptic

Answer 4

reduce glutamate (excitatory) transmission

Question 5

Which anti-epileptics work in all forms of epilepsy?

Answer 5

lamotrigine
levetiracetam

Question 6

Which anti-epileptics can be used in almost all types of epilepsy?

Answer 6

valproate
carbamazepine

Question 7

What drug is used in absence seizures?

Answer 7

ethosuximide

Question 8

Lamotrigine side effects/interactions

Answer 8

severe skin reactions in children
blood disorders
interaction with valproate

Question 9

What is a key risk of valproate?

Answer 9

teratogenicity
must not be used in women of childbearing age

Question 10

What does carbamazepine act on that means it has many drug reactions?

Answer 10

p450 system

Question 11

When can anti-epileptic drugs be stopped?

Answer 11

suggest a 2 year seizure free interval before gradually stopping over 3-6mo
no driving during withdrawal and until 6mo after

Question 12

What is the risk of anti-epileptic drugs in pregnancy?

Answer 12

risk of craniofacial and neural tube defects
if pregnancy is planned, try to withdraw drug before conception

Question 13

General adverse effects of anti-epileptic drugs

Answer 13

dizziness, ataxia, blurred vision, nystagmus, cerebellar signs
blood disorders (folic acid related with phenytoin)
abnormal liver function (severe with valproate in children)

Question 14

What drugs should be used in status epilepticus?

Answer 14

Benzodiazepine IV - diazepam or lorazepam (max 2 doses due to resp depression)

2nd line = levetiracetam, phenytoin, valproate infusion

3rd line = ITU - sedation - thiopentone or propofol or midazolam

Question 15

How can dopamine levels be increased?

Answer 15

give dopamine precursor - L-DOPA

or dopamine agonist - bromocriptine, cabergoline, pergolide, pramipexole

or reduce body’s breakdown of existing dopamine, ie inhibit enzymes that metabolise dopamine - MAO-B inhibitor (selegiline), COMT inhibitor (tolcapone)

or release dopamine from stores and inhibit reuptake - amantadine

Question 16

What converts L-dopa to dopamine?

Answer 16

dopa-decarboxylase

Question 17

What does peripheral dopamine formation cause?

Answer 17

nausea and vomiting
postural hypotension

Question 18

Why is giving peripheral dopa decarboxylase inhibitor (eg. carbidopa, benserazide) with L-dopa good?

Answer 18

smaller doses of L-dopa required
less adverse effects
smoother plasma concentration
inhibitor doesn’t penetrate CNS so doesn’t worsen Parkinson’s

Question 19

What medications can be used in acute migraine?

Answer 19

paracetamol, ibuprofen, aspirin
prochlorperazine, metoclopramide
triptans

Question 20

What drugs can be used in migraine prophylaxis?

Answer 20

propranolol
amitriptyline
topiramate

Question 21

What condition should triptans not be used in?

Answer 21

cardiovascular disease - triptans are vasoconstrictors

Question 22

When should drug prophylaxis be commenced with migraines?

Answer 22

> 3 attacks monthly
moderate-severe
or substantial disability