Neurological Phamacology Flashcards
Describe the three classic motor symtoms of Parkinson’s Disease. (6)
Tremour - low frequency, pill rolling
Rigidity - cog wheeling and lead pipe
Bradykinesia - only responds to dopaminergic drugs.
Describe non-motor symtoms of Parkinson’s disease. (6)
Mood changes, pain, cognitive change, urinary change, sleep disorders, sweating.
Describe the diagnostic criteria for Parkinson’s Disease. (3)
No structural abnormalities on imaging.
Must be a response to dopaminergic drugs.
No other cause of Parkinsonism - drugs, vascular, degeneration.
Describe the special scan used to diagnose Parkinson’s disease and the findings in PD. (2)
A DAT scan labels the ability to reuptake dopamine in the brain.
In PD it will be asymmetrical.
Describe the pathophysiology of PD. (3)
Neurodegeneration of dopaminergic neurones in the substantia nigra leading to Lewy Body deposition. A 50% loss of neurones leads to symptomatic PD.
Describe the pathway of conversion between intermediates of the production and degradation of dopamine. (11)
Tyrosine > L-DOPA >(DOPAdecarboxylase)> Dopamine > Noradrenaline > adrenaline
Dopamine >(monoamine oxidase)> Intermediate >(Catechol-O-methyl transferase)> Homovanillic acid.
Describe the mechanism of action of LDOPA. (2)
Taken up by dopaminergic cells in the substantia nigra and converted to dopamine there.
Explain why LDOPA can’t be taken with certain meals. (2)
Absorbed through the intestinal wall by active transport in competition with amino acids. Can’t be taken with a high protein meal.
What is the T1/2 of LDOPA? (1)
2 hours.
Explain why LDOPA is often given in conjunction with an enzymatic inhibitor. Name this inhibitor. (5)
DOPA decarboxylase inhibitor
Only 1% of LDOPA reaches the CNS: 90% inactivated in the intestinal wall, and 9% is converted in the peripheral tissues and then can’t cross the BBB.
Given with this inhibitor to prevent peripheral conversion to increase the amount that reaches the brain.
Explain why LDOPA can get less efficacious as a treatment over time. (2)
It needs functional dopaminergic neurones in the substantia nigra, but as the disease progresses, these are lost.
Describe 2 advantages of LDOPA as a treatment for PD. (3)
Initially highly efficacious
Low occurance of side effects - nausea, hypotension, paychosis, tachycardia.
Describe 3 disadvantages of LDOPA as a treatment for PD. (3)
Given as a precursor which needs enzymatic conversion.
Long term loss of efficacy.
Motor complications like freezing or dystonia.
Describe 2 DDIs of LDOPA. (2)
Vitamin B6 suppliments prompts peripheral conversion of LDOPA.
Antipsychotics block dopamine receptors (why they have Parkinsonism as a side effect).
Describe the three classes of dopamine receptor agonist. Give an example of each, and give their indications. (13)
Non-Ergot - Ropinirole, Pramipexole - add on therapy.
Patch - Rotigotine - if can’t take LDOPA orally.
Subcutaneous - Apomorphine - severe motor complications only.