In order to better understand the effect of apomorphine used as a rescue drug, I think it is worth drawing graphs of levodopa equivalent plasma levels over the course of a day, with and without a dose of apomorphine, and with and without a dose delayed due to, for instance, eating protein.
I have written an app to do that. See:
Parkinson's Disease Measurement: PwP, surveys, trials, analysis
All the references to the literature are there.
(You can use this tool yourself. Just go to the web page, input details of your drug regimen and the program will draw the graph for you.)
Note that the pharmacokinetic parameters used are from a intra nasal version of apomorphine, and not from the sub-lingual version, Sunovion, but I wouldn't expect them to be greatly different.
In all the scenarios below the "on" threshold is set at 50 LED mg. This figure will vary greatly from person to person.
In the graphs below, the coloured lines show the contribution made by each of the doses. The black line shows the total at each time. The horizontal green line at 50 is the assumed "on" threshold.
Scenario 1. Five doses of 100mg levodopa/carbidopa taken at 0700, 1000, 1300, 1600 and 1900.
Plasma max (LED mg) = 127
On duration (min) = 760
Off duration (min) = 680
original.png
***************************
Scenario 2. Five doses of 100mg levodopa/carbidopa taken at 0700, 1000, 1300, 1600 and 1900. But, due to, for instance, protein in the diet, the 1300 dose's action is delayed by 60 minutes and, then, only delivers 70% of the normal amount of levodopa.
Plasma max (LED mg) = 131
On duration (min) = 700
Off duration (min) = 740
delayedDose.png
***************************
Scenario 3. As scenario 2, but additionally a 10mg dose of apomorphine is taken at 1400, because there is an unexpected "off".
Plasma max (LED mg) = 244
On duration (min) = 723
Off duration (min) = 717
apomorphine.png
***************************
Obviously the answer will vary from person to person, but the question that this raises is:
Is the extra 23 minutes of "on" time worth the near doubling of levodopa equivalent peak plasma levels, and the effect that this may have on dyskinesia?
John