A few weeks ago I wrote a post describing an app that I'd written to add together the contributions made by the various anti-Parkinson's drugs that we take. It used the idea of levodopa equivalent dose as a common denominator. For instance, 1mg of rasagiline makes about the same total contribution as 100mg levodopa (taken with carbidopa). This approach can be improved by taking into account the timing of the doses and the different durations of effectiveness of the different drugs. For instance, rasagiline is effective for the whole 24 hours, whereas levodopa lasts for about 4 hours. Roughly speaking, therefore, levodopa is 6 times stronger than rasagiline, but the rasagiline lasts about 6 times as long.
I've written an app to do the calculations and draw the graphs. You just enter the times of your doses and what they contain. See:
Unfortunately, there's no agreement in the scientific literature as to the exact pharmacokinetic parameters to use. I've chosen default values that I think are reasonable, but you can override them if you wish.