PARKINSONS, SEIZURES, STROKES, MIGRAINES Flashcards
What are the 3 pharmacological targets for treating parkinsons?
Increase dopamine levels
Reduce dopamine breakdown - MAO-B inhibitors or COMT inhibitors
Directly act on dopamine receptors
An example of a drug that directly increases dopamine levels in the pharmacological management of Parkinson’s disease?
Levodopa
Examples of drugs that reduces dopamine breakdown in the pharmacological management of Parkinson’s disease?
MAO-B inhibitors - selegiline and rosagiline
COMT inhibitors - entacapone and tolcapone
An example of a drug that directly acts on dopamine receptors in the pharmacological management of Parkinson’s disease?
Pramipexone
Ropinirole
Rotigotine
Give examples of MAO-B inhibitors?
Selegiline
Rasagiline
Give examples of COMT inhibitors?
Entacapone
Tolcapone
What drugs are typically offered for Tx of parkinsons disease when its the early stages and the motor symptoms are not impacting on QOL?
Dopamine agonists or MAO-B inhibitors - this can delay the need for levodopa
How are COMT inhibitors used in the Tx of parkinsons disease?
They are often given as adjuvant therapy alongside levodopa as they prevent it from breaking down, potentiating the effects
What is levodopa?
Why can’t we just give dopamine directly to treat parkinsons disease?
An amino acid precursor of dopamine
As dopamine cannot cross the blood brain barrier but levodopa can and then levodopa is converted to dopamine within the brain
What is carbidopa and benserazide? Why do we give it alongside levodopa?
They are dopadecarboxylase inhibitors
Dopadecarboxylase can convert levodopa peripherally into dopamine
So we give a dopa decarboxylase inhibitor alongside levodopa to prevent it being converted to dopamine before it reaches the brain.
This means more of the drug can act within the central NS but also we dont get excessive dopamine peripherally
Central physiological effects of dopamine?
Psychosis and mania
Impaired cognition e.g. memory, attention, executive function
Restlessness and agitation
Suppress lactation
Peripheral effects of too much dopamine?
Nausea and GI effects
Anti-kinetic effects on the GI system
Vasoconstriction
Peripheral efefcts of too much dopamine?
GI e.g. nausea
Anti-kinetic effects on GIT
Vasoconstriction
Which groups of pt should never be prescribed medications containing levodopa?
Severe psychiatric illness
Severe pulmonary or cardiovascular disease
Severe nausea or GI motility problems
Breast feeding
Common and important side effects of co-careldopa and co-beneldopa?
N&v
Abnormal dreams and sleep disturbances
Dizziness and syncope
Dyskinesia
Rapid fluctuations in clinical state
Postural hypotension
Psychological effects
Impulse control disorders - pathological gambling, binge eating and hypersexuality
Interactions of co-careldopa and co-beneldopa?
Monoamine oxidase inhibitors
General anaesthetic
Anti-hypertensives
What must you communicate to the patient when they start co-careldopa or co-beneldopa?
The side effects
Not to stop abruptly as can cause maligannt neuroleptic syndrome
They can cause postural hypotension so esp in elderly warn them of this
Warn them of sleepiness if they drive or work
What is co-careldopa?
A mixture of carbidopa and levodopa
What is co-beneldopa?
A combination of benserazide and levodopa
What should you do if the pt on levodopa treatment is experiencing the wearing off phenomenon?
Adjust the dose to smaller, more frequent doses
Use prolonged-release levodopa preperations and take at bedtime
Advise about taking levodopa 30 mins before food to enhance the absorption
What does it mean to Call levodopa a time critical drug?
It must be taken at the same time exactly each day to avoid the wearing off phenomenon
This is why in A&E if you get a pt you cannot trust the electronic records you MUST ask the pt how they take their levodopa at home and continue this routine exactly
What are the “on-off” fluctuations seen in levodopa treatment?
When the drug is working and symptoms are well controlled and then suddenly/gradually the drug isnt working and motor symptoms appear e..g during the wearing off phase
Can also mean when patients switch from severe dyskinesia to immobility in a few minutes
How can we help a pt struggling with on-off fluctuations when on levodopa treatment?
Combine levodopa with a dopamine agonist
Give fewer doses of levodopa
Use liquid forms of levodopa
What should you do as an F1 if you think the pt does not require their parkinsons meds?
NEVER ABRUPTLY DISCONTINUE PARKINSONS MEDICATIONS WITHOUT A SPECIALIST ADVICE
Options for levodopa if pt are unable to swallow?
Crush tablet (not if modified release!!)
Consider liquid
Patch
NG/NJ/PEG tube
What is the transdermal drug that can be given for parkinsons called? Whats its MOA?
Rotigotine - a dopamine agonist
Why should you not stop parkinsons drugs abruptly?
Neuroleptic malignant syndrome - a rare but life threatening condition!!
Pathophysiology of neuroleptic malignant syndrome?
Blockage of D2 receptors in the hypothalamus results in elevated temperature set point and impairment of heat-dissipating mechanisms
Blockages of D2 receptors in the nigrostriatal pathway results in muscle rigidity
Symptoms of neuroleptic maligannt syndrome?
Pyrexia
Muscle rigidity
Autonomic lability e.g. hypertension, tachycardia, tachonoea
Agitated delirium with confusion
Management of neuroleptic maligannt syndrome?
Stop offending drug if that’s the cause
IV fluids
Dantrolene may be used in selective cases (a muscle relaxant)
Bromocroptine may also be used
When considering an AED, what factors influence the choice of treatment?
The type of seizure
Age
Tolerance, compliance, SE
Gender - for pregnancy
Lifestyle - occupation and driving
Coexisting medical condition or medications
First line Tx for tonic-clinic seizures?
Sodium valproate first line in males and females unable to conceive
Lamotrigine or levetiracetam second line or for fertile females
First line Tx for absence seizures?
Ethosuximide
First line Tx for myoclonic seizures?
Sodium valproate in males and infertile females
Levetiracetam in fertile females