Neurophysiology pharmacology Flashcards
3 causes of status epilepticus
Compromised airway
Metabolic disturbance
Neuronal excitotoxicity/hypoxia.
How do you treat status epilepticus?
1) Minimise hypoxia by using high flow O2 and securing airway.
2) Terminate event by using a fast acting CNS depressant. If no response
3) Load with IV anti-epileptic e.g phenytoin, levetiracetam or sodium valproate.
What are the fast acting CNS depressants and when do you use them?
Lorazepam
Diazepam (if lorazepam unavailable)
Buccal midazolam (if others unavailable or no IV access
Rectal diazepam (last line)
When would you use buccal midazolam?
To terminate status epilepticus when there is no IV access.
How would you investigate someone with status epilepticus?
Imaging for structural disturbance Electrolytes for imbalance FBC ABG for metabolic disturbance CXR for aspiration Toxicology if cause unknown.
If alcohol withdrawal is suspected in someone with status epilepticus, how do you treat?
- 50 ml of 50 % glucose IV and
* One pair of pabrinex ampoules IV
What monotherapy would you start in someone with a primary generalised tonic clonic seizure?
Sodium valproate
Carbamazepine
or
Phenytoin
What monotherapy long term treatments would you use in an epileptic with a partial secondary generalised seizure?
Sodium valproate
Carbamazepine
or
Phenytoin
What monotherapy treatment would you use in someone with an absence seizure?
Sodium valproate
Ethosuxemide
What monotherapy would you use in an atypical absence seizure which is myoclonic and atonic.
Sodium valproate or levetiracetam.
What are the types of drug treatment for severe or recurrent depression?
Prevent monoamine reuptake or breakdown.
Enhance monoamine related neurotransmission.
Which drugs prevent monoamine reuptake and what are they used for?
TCAs, SSRIs, venlafaxine
Used for depression
Which drugs prevent monoamine breakdown and what are they used for?
MAOIs
Used in depression
Which drug enhances monoamine related neurotransmission?
Mirtazapine (used in depression)
What do SSRIs do?
Block pre-synaptic reuptake of 5-HT via SERT. So increase 5HT activity.
What do TCAs do?
Block pre-synaptic uptake of NA and 5-HT via SERT and NAT.
What does mirtazapine do?
Blocks autoreceptors so prevents negative feedback, so NA and 5-HT release is maintained.
What does venlafaxine do?
Block pre-synaptic reuptake of NA nad 5-HT via SERT and NAT. Possibly affects DA reuptake.
What do MAOIs do?
Inhibit enzymatic breakdown of monoamines.
When should a TCA dose be given?
At night - it has marked sedative properties.
What should you be careful of in TCA use?
Overdose - can be cardiotoxic.
Marked anti-cholinergic effect.
How do anti-psychotics work?
By antagonising or modulating CNS dopamine signalling.
What should you be worried about with rapid tranquillisation of a patient with acute psychosis (which may be necessary)
Airway obstruction Resp depression Hypotension Coma Seizure NEUROLEPTIC MALIGNANT SYNDROME.
Observed symptoms of Parkinson’s disease
Bradykinesia
Tremor
Rigidity
Therapeutic targets in Parkinson’s disease
Replace, stimulate release of or mimic DA at synapses.
Inhibit DA metabolism via MAO-B
Inhibit DA metabolism via COMT
Reduce influence of ACh
Dopamine receptor agonists used in Parkinson’s disease.
Rotigotine
Ropinirole
Pramipaxole
Apomorphine
Dopamine stimulating drug.
Amantadine
Drug increasing DA synthesis
L-DOPA
What are a few MAO-B inhibitors?
Selegilin
Rasageline
Used in Parkinsons
What is entacapone?
A COMT inhibitor used to potentiate effects of L-DOPA.
What drug classes are most commonly involved in interactions?
Transplant anti-rejection drugs
Antibiotics
Anti-epileptic drugs
TDM drugs
Which transplant anti-rejection drugs are commonly involved in interactions?
Ciclosporin
Tacrolimus
Sirolimus
Which TDM drugs are commonly involved in interactions?
Phenytoin, digoxin, lithium,
aminophylline, theophylline.
Which anti-epileptics are commonly involved in interactions?
Carbamazepine
Which antibiotics are commonly involved in drug interactions?
Macrolides
Which two drugs are very commonly involved in dangerous interactions?
Warfarin and Methotrexate.
