Parkinson's disease management

Examples: Sinomet, Madopar

Levodopa = dopamine precursor which is able to cross the blood brain barrier. Must be given with DDCI to prevent peripheral conversion to dopamine (reduce S/E)

Most effective treatment in PD: motor Sx improve in 20-70%

Short term S/E: N+V, decreased appetite, postural hypotension, confusion, visual hallucinations, delusions, sleep disturbance, tolerance develops over a few weeks (start low and go slow)

Long term S/E: tolerance (need to increase dose over time, so often use adjuvant Rx to prevent S/E), dyskinesias (occur in 50% patients after 6yrs and 100% yound patients after 6yrs), end-of-dose deterioration, unpredictable on/off switching, confusion, hallucinations

Mgmt of motor complications: fractionate dose, adjuvant Rx (dopamine agonist, COMT inhibitor, MAOI), DuoDopa, Apo infusion, deep brain stimulation

Examples: rotigotine, ropinirole, pramipexole (no longer use ergot-derived DAs e.g. bromocriptine, pergolide due to serosal complications- pericardial/pleural effusions- and cardiac valve abnormalities)

Common S/E:

• N+V
• loss of appetite
• postural hypotension
• confusion, hallucinations
• somnolence
• impulse control disorders (must warn patients before starting/increasing treatment, usually settle after withdrawal of meds)

Irreversible inhibitors of MAOB. Cause decreased breakdown of dopamine so more is left in the synaptic cleft.

Examples: selegiline, rasagiline

Weak clinical effect- use in very early disease or as an add-on

Well-tolerated, may have neuroprotective effects

S/E: 

• N+V
• confusion
• may interact with SSRIs (serotonin syndrome)

Increase amount of levodopa that crosses the blood-brain barrier to produce prolonged effect of levodopa

Examples: entacapone, tolcapone (Stalevo = Sinemet + entacapone)

S/E:

• as with others
• diarrhoea
• discolouration of body fluids
• increased dyskinesias

Antiviral, mostly used in later disease (treats dyskinesias)

Increases dopamine release

Should not be used in the elderly

S/E:

• confusion
• hallucinations and psychosis
• livedo reticularis
• ankle oedema

Examples: trihexyphenidyl, benztropine, orphenadrine, procyclidine, biperiden

Rarely used except in young patients with prominent tremor

Decreases effects of relatively central Ach excess

S/E:

• cognitive impairment (especially in elderly)
• dry mouth
• blurred vision
• constipation
• dizziness
• urinary retention
• glaucoma