Neurological Drugs Flashcards

1
Q

What is lamotrigine

A

An anti-convulsant

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2
Q

Indications for the use of lamotrigine

A

1) Treats seizures
2) seizures associated with Lennox-Gastaut syndrome
3) Clinical depression - used off label

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3
Q

What is lennox-gastaut syndrome

A

A severe seizure disorder of young people

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4
Q

How does lamotrigine work

A

Sodium channel blocker - inhibits glutamate release hence having an anti-convulsant activity

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5
Q

Adverse effects of lamotrigine

A
Rashes
Flu-like symtpoms
Visual disturbances
Diszziness
Drowsiness
GI disturbances
Aggression
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6
Q

Warnings of the use of lamotrigine

A

Contraindicated in hepatic and renal impairment!!!

Use in pregnancy only if the risks dont outweigh the benefits

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7
Q

Interactions of Lamotrigine

A

OCP, carbamzazepine, ritonavir, phenytoin and rifampicin –> all decrease its concentration as it induces its glucorindation

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8
Q

Interactino of lamotrigine with valproate

A

Increases its concentration as valproate inhibits its glucorination

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9
Q

What is levitaracetam

A

An anti-convulsant

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10
Q

What do we use levitaracetam for?

A

1) Epilepsy - partial-onset, myoclonic or tonic-clonic seizures

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11
Q

How does levitaracetam work

A

Binds to synaptic vesicle glycopratein, SV2A, inhibts presynaptic calcium channels
This reduces neurotransmitter release –> acts as a neuromodulator
Impedes conduction across synapses

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12
Q

Adverse effects of levitaracetam

A

CNS effects –> most pronounced in the first month (somnolence, fatigue, headaches, dizziness, coordination problems)

Neuropsychiatric symptoms –> agitation, hostility, apathy, depression, suciidal thoughts

SJS and TEN

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13
Q

Warnings of use of levitaracetam

A

Reduce dose in renal impairment

Cautin in pregnanct

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14
Q

Interactions of levitaracetam

A

No significant drug interactions

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15
Q

What is phenytoin

A

An anti-convulsant

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16
Q

Indications of phenytoin

A

1) Status epileptics - if benzodiazepines are ineffective

2) Epilepsy - reduce frequency of generalised or focal seizures

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17
Q

Actiosn of phenytoin

A

Reduces neuronal excitability and electrical conduction among brain cells
Binds to neuronal Na+ channels in their inactive state
Also similar effect in cardaic Purkije fibres –> accoutns for antiarrhytmic and cardiotoxic effects

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18
Q

Adverse effects of Phenytoin

A

1) Appearance change - can corase skin coarsening, acne, hirsutism, gum hypertrophy

2) Neuro effects –> cerebellar toxicity
3) Haematological disorders and osteomalacia –> inducing folic acid and vitamin D metabolism
4) Hypersensitivity
5) CV collapse and respiratory depression - if phenytoin toxicity

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19
Q

Effects of phenytoin overdose

A

CV collapse and respiratory depression

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20
Q

Warning of using pheytoin

A

Metablised by liver at zero order kinetics

Low therapeutic index

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21
Q

Reduce dose of phenytoin in

A

Hepatic impaiment

22
Q

Use of phenytoin in pregnancy causes what

A

Fetal hydantoin Syndrome
Causes craniofacial abnormalities ad a low IQ
Discuss with specialist and take folic acid supplements before conception

23
Q

Interactions of phenytoin

A

Phenytoin inducers P450 enzymes

However it is also metablised by P450 enzymes - hence CP450 inhbiitos increase its effect

24
Q

Name some CP450 inhibitros

A

Amiodarone
DIltiazem
Fluconazole

25
What type of drugs also lower the threshold potential causing the efficacy of phenytoin to reduce
SSRIs and tricuclic antidepressants
26
What do we need to ensure we do after giving phenytoin via a cannula
Flush the cannula to prevent venous irritation | Give it into a large vein
27
What is carbamazepine
An anti-convulsant
28
Indications of carbamazepine
1) Epilepsy 2) Trigeminal neuralgia --> First choice to control pain and reduce frequency and severity 3) Bipolar disorder - prophylaxis option
29
Action of carbamazepine
Appears to nihibit neuronal sodium channels Stabilizes resting potentials and reducing neuronal excitability Stops spread of seizure activity Stabilises mood in bipolar --> reduces electrical kindling in the temporal lobe and limbic system
30
Adverse effects of carbamazepine
1) GI Upset 2) Neuro effects - dizziness and ataxis 3) Hypersensitivity - mac pac rash affects 10% of peoples 4) Antiepileptic hypersensitivity syndrome
31
What is anti-epileptic hypersensitivity syndrome
Usually starts within 2 months of treatment Severe skin reactions Fever Lymphadenopathy Systemic involvement (haematological, hepatic and renal)
32
Warnings of carbamazepine
1) In utero causes foetal abnormalities | 2) Prior anti-epileptic hypersensitivity syndrome is a contraindication
33
Caution of using carbamazeinpine in
Hepatic Renal Cardiac disesae Increased risk of toxicity
34
Interactions of carbamazepine
Carbamazepine is metabolised by CPP450 enzymes It is also an inducer of CP450 enzymes itself Also beware of other drugs that lower the threshold potential as these decrease its efficacy e.g. SSRIs, tricyclicl anti-depressants and antipsychotics and tramadol
35
What is valproate
An anti-convulsant
36
Indications of valproate
1) Epilepsy - 1st choice | 2) Bipolar - acute treatment of manic episodes and prophylaxis against recurrence
37
Action of valproate
Weak inhibitor of neuronal sodium channels | Also increases GABA in the brain content
38
Adverse effects of valproate
GI Upset Neuro and psychiatric effects: tremor, ataxia, behavioural distrubances Thrombocytopenia and transient increase in liver enzymes Hypersensitvity reactions Rare life threatening idiosyncratic reactions
39
Who shoudl you avoid valpraote in
Child-bearing age, around time of conceptino and the first trimester
40
Who should we avoid valproate in
Pregnancy Hepatic impairment Dose reduction if renal impairment
41
Interactions of valproate
Itself inhibits CP450 enzymes Valproate itself is metablised by the CP450 enzymes Also be aware of drugs that lower the threshold potential as these reduce its efficacy
42
What should we warn patients about when they start taking valproate
Tummy upset | Urgent medical advice if they have lethargy, loss of apetite, vomiting and abdo pain
43
Indications of L-Dopa
1) Parkinsons disease - in earlier generally use dopamine agonists but L-DOPA is integral in later treatment 2) Treatment of secondary parkinsons
44
Action of L-Dopa
Levodopa - a precursor of dopamine that enters the brain via a transporter
45
What are ropinorole and pramipexol
Dopamine agonists - these are relatively selective
46
Pathogenesis behind parkinsons
Deficiency of dopamine in nigro-striatial pathway - therefore via direct and indirect pathways the basal ganglia exert greater inhibitory effects on the thalamus --> this reduces excitatory input to the motor cortex hence causing symtpoms e.g. bradykinesia
47
What is simenet and madopar
These are L-Dopa
48
Adverse effects of L-Dopa
Nausea, drowsiness, confusion, hallucinations, hypotension Wearing off effect --> symptoms worsen at end of dosage interval On-Off effects
49
Cautions of L-Dopa
Cauting in elderly.existing cogntiive/psychiatric disease duet o risk of confusion/hallucinatinos Caution in cardiovascular disease --> risk of hypotension
50
What do we always need to prescirbe l-dopa with
a peripheral dopa-decarboxylase inhibitor e.g. carbidopa --> to reduce its conversion to dopamine outside the brain
51
What should you not comibne L-DOPA with
Antipsychotics --> particularly first generation and metacloparamide due to contraidctory effects on receptors