Senior Member
|
|
Join Date: Apr 2009
Location: Stafford, UK
Posts: 1,059
|
|
Senior Member
Join Date: Apr 2009
Location: Stafford, UK
Posts: 1,059
|
Levodopa: do you feel worse for a few minutes after the first dose?
Boxtel et al. write [1]:
"Classically, the worsening of clinical signs in patients given very low dose antiparkinsonian drugs is explained by a preferential stimulation of presynaptic dopaminergic receptors ... limiting release of endogenous dopamine."
This observation complicates the prescribing process: a baseline result, followed by a negative result is not, in itself, adequate to conclude that an antiparkinson medication is not efficacious.
It may also explain why I perform fairly well in the morning before taking the first dose of the day, but get worse briefly while the drug's absorbed up to working levels. I often go 12 hours, 8 half-lives of levodopa, overnight between doses, so the drug has almost been washed out.
It also suggests that too much exogenous levodopa may lead to a decrease in endogenous dopamine production. This would favour the "runway" hypothesis of dosing, rather than the, I think, currently favoured "use or lose" hypothesis.
Reference:
[1] "Drug Benefits and Risks: International Textbook of Clinical Pharmacology"
edited by C.J. van Boxtel, B. Santoso, I.R. Edwards
John
__________________
Born 1955. Diagnosed PD 2005.
Meds 2010-Nov 2016: Stalevo(75 mg) x 4, ropinirole xl 16 mg, rasagiline 1 mg
Current meds: Stalevo(75 mg) x 5, ropinirole xl 8 mg, rasagiline 1 mg
|