Parkinson's disease in practice Flashcards
what is PD?
•Chronic, progressive neurodegenerative
condition
•Loss of the dopamine-containing cells of the
substantia nigra
•Bradykinesia together with at least one of the
following: rigidity, tremor, and postural
instability
•Features usually present unilaterally initially,
but become bilateral as the disease
progresses
who is PD most common in?
elderly- prevalence of 1-2% in people older than 65 years
what are motor complications usually related to?
use of anti-parkinsonian medication
what are some motor complications associated with PD?
- Deteriorating function
- Loss of drug effect
- Motor fluctuations
- Dyskinesia
- Freezing of gait
- Falls
what are non-motor complications usually symptoms of?
symptoms of the disease or adverse effects of medication
what are some antonomic dynsfunctions caused by the medication?
–Constipation –Orthostatic hypotension –Dysphagia and weight loss –Excessive salivation and sweating –Bladder and sexual problems
what is neuroleptic malignant syndrome?
Rare, life-threatening idiosyncratic reaction
•May occur if dopaminergic drugs are stopped abruptly
•Symptoms include fever, altered mental state, muscle rigidity, raised CK, and autonomic
dysfunction
how do you manage NMS?
–IV fluids –Correct any metabolic abnormalities –Cooling – blankets –IV dantrolene –Restart PD medications
what is the function of levodopa?
•First line in NICE guidelines for people in early
stages of PD whose motor symptoms impact
of their QoL
•Improve motor symptoms and activities of
daily living, with few adverse effects
what complications can levodopa cause?
can lead to more motor complications
how should you initiate levodopa?
start at low dose and titrate up
how does levodopa work?
it is converted (decarboxylated) to dopamine in the
brain
what is levadopa coadministered with?
•Levodopa formulations also contain benserazide
(co-beneldopa) or carbidopa (co-careldopa)
–No therapeutic effect on their own
–Dopamine can’t cross blood brain barrier (BBB)
how does the co-administration of levodopa work?
–Inhibit peripheral decarboxylation of levodopa before
it crosses the BBB
what are the problems associated with levodopa?
•Becomes less effective over time •Experience ‘wearing off’ •Long term use can result in dyskinesia •Impulsive and compulsive behaviours •Withdrawal symptoms •Common side-effects – N&V, hypotension, reduced appetite, hallucinations, sleep disturbances
how should you take levodopa?
Absorption reduced when administered with
iron – separate
•Absorption reduced when administered with
protein – some patients take 30-60 minutes
before a meal
what can happen if you take levodopa on an empty stomach?
–Can cause N&V on empty stomach – can advise to
take with a low protein snack e.g. crackers
how can you improve n/v caused by levodopa?
Some patients take most of daily protein in
evening to improve daytime symptoms
what are the forms of levodopa availible?
Co-beneldopa (Madopar®)- can come as dispersible tabs also
Co-careldopa (Sinemet®, Sinemet Plus®)- can come as gel also
who are DA agonists a good choice of treatment for?
in the early stages of PD whose motor symptoms do not impact on their quality of life
how do DA agonists work?
Act directly on dopamine receptors to mimic
effect of dopamine
what are the two subclasses of DA agonists?
–Ergot derived e.g. cabergoline, bromocriptine,
pergolide
•No longer recommended due to risk of pulmonary,
retroperitoneal, and pericardial fibrotic reactions
–Non-ergot derived e.g. pramipexole, ropinirole,
rotigotine, apomorphine
what are some problems with DA agonists?
•Fainting or dizziness •Sudden onset of sleep •Impulsive or compulsive behaviours •Hallucinations or delusions •Withdrawal •Other common side-effects: Nausea, constipation, hypotension, headaches, anxiety, depression, movement problems
what caution should you be aware of with pramipexole?
Caution: BNF doses and strengths are stated in
terms of pramipexole (base) but some literature
refers to salt form
what should you be cautious about when dispending ropinirole?
–Commonly LASA error – mixed up with risperidone
–Dose adjustment might be necessary if smoking
started or stopped during treatment
–If dose missed for one day or more, re-initiation
by dose titration should be considered
how should you take rotigotine?
–24 hour patch
–Contains aluminium – remove for MRI scan or
cardioversion
–Useful if swallowing difficulties
–Can cause skin irritation – use different site each
day
how is apomorphine given?
–Subcutaneously via disposable pen, cartridge pen
or infusion pump (using pre-filled syringe,
ampoules or vials)
how long does it take apomorphine to work?
Works within 5-10 minutes – injections used as
‘rescue treatment’
what are the s/e of apomorphine, what should be given before treatment starts?
–Causes nausea and sickness – domperidone given
2 days before treatment starts
who are MAO-b used in?
Potential choice for people in the early
stages of PD whose motor symptoms do not
impact on their quality of life
how do MAO-b work?
Inhibit the breakdown of dopamine by MAO-B
what are the problems associated with MAO-Bs?
- Interact dangerously with antidepressants
- Worsen levodopa side-effects e.g. dyskinesia (may need to reduce dose of levodopa)
- Impulsive and compulsive disorders
- Withdrawal
what other side effects are there with MAO-Bs?
Headaches, constipation, dry mouth, aching joints, indigestion, urinary urgency
what caution should you be aware of with MAObs?
Risk of hypertension when high-dose selegiline is taken with tyramine-rich foods
–Specific for MAO-B at low doses used for PD (5-10mg) so no dietary restrictions
how should you take MAObs?
•Rasagiline –Once a day •Selegiline –Once a day –Selegiline oral lyophilisate if swallowing difficulties •tablet placed on tongue and disperses within 10 seconds –patient cannot drink, eat or rinse mouth out for 5 minutes after taking •1.25mg equivalent to 10mg tablet •Safinamide –Once a day
who are COMT inhibitors good for?
Adjunct to levodopa for people who
have developed dyskinesia or motor
fluctuations despite optimal levodopa therapy
•Improve motor symptoms and activities of
daily living
•Reduce ‘off’ periods
•BUT more adverse effects
how do COMT inhibitors work?
Inhibit peripheral methylation of levodopa to 3-
O-methyldopa, allowing more levodopa to reach
the brain
what are the problems with COMT inhibitors?
•Colour urine bright red/orange
•Diarrhoea
•Risk of fatal liver damage with tolcapone
•Worsen levodopa side-effects e.g. dyskinesia,
N&V
•Impulsive and compulsive behaviours
•Common side-effects – confusion, dizziness, dry
mouth, falls, hallucinations, sleep disorders, chest
pain, fatigue
how should you take entacapone?
–Take at same time as levodopa –Combination product: co-careldopa and entacapone (Stalevo®) –Avoid taking at same time as iron supplements – reduce absorption
how should you take opicapone?
–Taken at bedtime, 1hour before or after levodopa
when is amantadine used?
Consider as an adjunct if dyskinesia is
not adequately managed by modifying
existing therapy
how does amantadine work?
Glutamate antagonist
why is it so important to give PD medicine ontime?
If people with PD don’t get their medication at
the right time it can seriously impact their health:
–Reduced movement
–Unable to get out of bed
–Unable to swallow, walk or talk
•Even a delay of 30minutes can be detrimental
what if someone with PD is nil by mouth?
Avoid abrupt withdrawal – can be life-threatening
•Need to convert critical oral medications to non-oral route:
–Via NG tube e.g. dispersible co-beneldopa
–Topical patch e.g. rotigotine patch
when can you omit etacapone, seleginine, rasagiline and amantadine?
in acute situations
how do you convert to rotigotine patches?
•If NG not suitable, convert levodopa dose to
equivalent rotigotine patch (max. 16mg in total)
•If patient is dopamine agonist naïve, caution and
specialist review required asap as patients can be
sensitive to effects
–Risk of side-effects – vomiting, skin reactions,
hypotension, hallucinations increased confusion
–Usually start at lower dose (2-4mg) and increase
gradually over a period of days
what medications should you avoid in PD?
- Metoclopramide
- Prochlorperazine (Stemetil®)
- Haloperidol
- Chlorpromazine
- St John’s Wort
- Decongestants e.g phenylephrine
- Anticholinergics
