Wk 29 - Parkinson's disease in practice Flashcards
What is Parkinson’s?
Chronic, progressive neurodegenerative condition - due to loss of dopamine-containing cells of substantia nigra
How does PD usually present as?
Bradykinesia w/:
- Tremor
- Rigidity
- Postural instability
Unilateral initially then bilateral
What is Neuroleptic malignant syndrome?
- Rare life-threatening idiosyncratic reaction
- Occurs if dopaminergic drugs are stopped abruptly
What are the symptoms of NMS?
- Fever
- Altered mental state
- Muscle rigidity
- Raised CK
How do you manage NMS?
- IV fluids
- Correct metabolic abnormalities
- Cooling
- IV dantrolene
- Restart PD medications
What is the first line medication for people in early stages of PD whose motor symptoms impact their QoL?
Levodopa
What else does levodopa formulations contain?
- Benserazide (co-beneldopa)
- Carbidopa (co-careldopa)
Why does levodopa contain co-beneldopa/co-careldopa?
- No therapeutic on own
- Dopamine can’t cross BBB
- Inhibit peripheral decarboxylation of levodopa before crosses BBB
- Inc dopamine in brain
What are the problems w/ levodopa?
- Less effective over time
- LT = dyskinesia
- Impulsive + compulsive behaviours
- W/drawal symptoms
How do you take levodopa?
- Separate w/ iron bc red absorption
- Take 30-60 mins before meal bc abs red w/ protein
- N+V on empty stomach tf take w/ low protein snack
- Take daily protein in evening to improve daytime symptoms
What is used for people in the early stages of PD whose motor symptoms don’t impact their QoL?
Dopamine agonists + MAO-B inhibitors
- Used alone or combination w/ levodopa when wearing off/fluctuations
How do dopamine agonists work?
Act directly on dopamine receptors to mimic effect of dopamine
What are the 2 classes of dopamine agonists?
- Ergot derived
- Non-ergot derived
Why are ergot derived no longer used?
Risk of: Pulmonary + pericardial fibrotic reactions
Give examples of ergot derived drugs
Pergolide
Give examples of non-ergot derived drugs
- Pramipexole
- Ropinirole
- Rotigotine
- Apomorphine
What are the problems with dopamine agonists?
- Fainting or dizziness
- Sudden onset of sleep
- Impulsive or compulsive behaviours
- Hallucinations/delusions
- W/drawal
How do you take ropinirole?
- Adjust dose if stopped/started smoking
- If dose missed, re-initiate by titrating dose
How do you take rotiotine?
- 24hr patch
- Contains Al tf remove for MRI/cardioversion
- For swallowing difficulties
- Can cause skin irritation
How do you take apomoephine?
- SC via disposable pen, cartridge or infusion pump
- Works w/in 5-10 mins: used as rescue treatment
- Continuous infusion red off periods
- Can cause N+V - domperidone given 2 days before treatment starts
How do MAO-B inhibitors work?
Inhibit breakdown of dopamine by MAO-B
Give examples of MOA-B inhibitors
- Selegiline
- Rasagiline
What are the problems with MAO-B inhibitors?
- Interact dangerously w/ antidepressants
- Worsens levodopa s/e: dyskinesia
- Impulsive + compulsive disorders
- W/drawal
- HT in high dose selegiline w/ tyramine rich food
How do you take MAO-B inhibitors?
- Rasagiline: OD
- Selegiline: OD or oral lyophilisate if difficulty swallowing (tongue + disperse, can’t drink for 5 mins)
What do you take in adjunct to levodopa for people who have developed dyskinesia or motor fluctuations despite optimal levodopa therapy?
COMT inhibitors
How do COMT inhibitors work?
- Inhibit peripheral methylation of levodopa to 3-o-methyldopa allowing more levodopa to reach brain
- Used in combination w/ levodopa
Give examples of COMT inhibitors
- Entacapone
- Opicapone
- Tolcapone
What are the problems w/ COMT inhibitors?
- Urine bright red/orange
- Diarrhoea
- Hepatotoxic: talcopone
- Worsens levodopa s/e: dyskinesia + N+V
- Impulsive + compulsive behaviours
How do you take entacapone?
- Same time as levodopa
- Avoid taking same time as iron supplements: red abs
How do you take opicapone?
At bedtime, 1hr before/after levodopa
What is taken as an adjunct if dyskinesia is not adequately managed by modifying existing therapy
Amantadine: glutamate antagonist
What needs to be ensured when giving PD medication?
- Med name
- Formulation
- Timing
What happens when a patient is nil by mouth?
Convert to non-oral route:
- NG tube: dispersible co-beneldopa
- Topical patch: rotigotine patch
What can you omit during an acute situation?
- Entacapone
- Selegiline
- Rasagiline
- Amantadine
What are the side effects of the rotigotine patch?
- Vom
- Hypotension
- Skin reactions
- Hallucinations
Give examples of medications to avoid in PD
- Metoclopramide
- Prochlorperazine
- Haloperidol
- Chlorpromazine
- St John’s Wort
- Anticholinergics
