parkinsons Flashcards
What drugs may induce parkinsonism?
antipsychotics (block D2 receptors) e.g., haloperidol, trifluoperazine, chlorpromazine
* Metoclopramide (nausea, vomiting)
* Cinnarizine (Menière’s disease)
* Amiodarone (arrhythmias)
* Lithium (bipolar disorder)
* Methyldopa (hypertension)
What is the treatments options for symptoms of parkinsons?
- Levodopa (as co-careldopa or co-beneldopa)
- Dopamine receptor agonists, such as ropinirole
- Monoamine oxidase-B inhibitors, such as selegiline
- Catechol-O-methyltransferase (COMT) inhibitors, such as entacapone
What is levodopa combined with?
Co-careldopa: Levodopa and Carbidopa
Co-beneldopa: Levodopa and benserazide
Why is levodopa combined with another drug?
they Inhibit dopa decarboxylase from transforming levodopa into dopamine before it enters the brain reducing SE.
but both too polar to cross the BBB
What is the treatment guidelines?
- For pts whose motor symptoms affect QOL: Levodopa
- For pts whose motor symptoms don’t affect QOL: Dopamine agonists(ropinirole), levodopa, or selegiline
What are the limitations of using levodopa?
- Can cause levodopa-related motor disturbances which can very disabling and difficult to treat - can be worse than the disease itself
- Dyskinesias (involuntary muscle movements) – may not appear initially but develop in most patients within 2 years of starting levodopa therapy.
- On-off response – due to fluctuating dopamine levels in the brain, sudden and without warning. Off period = freezing. On period = uncontrollable movement
Wearing-off effect – effects of a dose don’t last as long as they used to - need more frequent and higher doses
What warning should patients and carers be informed about all dopamine agonists?
impulse control disorder may develop:
* Compulsive gambling
* Hypersexuality
* Binge eating
* Obsessive shopping
* doses should be reduced gradually, and patients monitored
What are the dopamine agonists that are used?
Non-ergot derived : Pramipexole, Ropinirole, Rotigotine (patch)
Ergot-derived (rarely used now due to cardiac valve and pulmonary fibrosis) : Bromocriptine, cabergoline, pergolide
Why is entacapone used?
Used adjunct to co-careldop – Entacapone (also in combination with co-careldopa (Stalevo))
prevents the peripheral breakdown of levodopa by inhibiting COMT, allowing more levodopa to reach the brain
Why is domperidone used?
Can be used for SE of Levodopa in periphery
Counteracts the emetic effect of levodopa without adversely affecting the antiparkinsonian (dopaminergic) effect of these drugs
Does not cross the blood-brain-barrier
What is neuroleptic malignant syndrome?
rare but potentially life-threatening idiosyncratic reaction to neuroleptic drugs - Causes fever, muscular rigidity, altered mental status and autonomic dysfunction
can be due to stopping abruptly or not giving at right times
How are drugs given to dysphagic pts?
!! Remember – all manipulations for formulations e.g., crushing, will deem it unlicensed !!
Co-careldopa and Entacapone: give separately (not as Stavelo)
* Dispersible alternative - Crush and mix with honey/jam/orange juice
Domperidone
* Dissolve in water
* Liquid formulation
