PARKINSONS (SEVERE) Tx-L DOPA

SUMMARY

1. L-dopa acts as a precursor for dopamine synthesis in the basal ganglia.

2. Carbidopa blocks conversion of L-dopa to dopamine in the periphery, desirable as peripheral dopamine does not cross the BBB & causes autonomic SE.

3. Most effective drug, but delay its use in the young to reduce side-effects.

4. Dopamine receptor agonists (ropinirole, pramipexole, rotigotine) and COMT inhibitors (entacapone) are added to reduce the overall daily dose of L-dopa.

5. SE: postural hypotension, on-off effects (unpredictable therapeutic levels), psychosis (particularly in the elderly).

6. Neuroleptic malignant syndrome: switching L-Dopa causes malignant hyperthermia, delirium, autonomic instability.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].