Renato,
I assume you're simply trolling people with this thread.
But if you're not, here's my $0.02:
If you feel that you cannot drive safely without the use of stimulants, you shouldn't drive.
If you feel that it is your advancing age that is limiting your ability to drive, you should probably submit yourself for further drivers' licence testing.
Advancing age doesn't just impair your tolerance for long-distance driving, but also the speed of your reflexes, and your ability to make appropriate judgements.
Although you allege that your brain has appropriate stimulants and glucose, that doesn't necessarily mean that your higher function centres are working well.
It seems to me that this is the second post within a year bemoaning your reducing abilities in the face of advancing age, so perhaps you should restrict yourself to more age- and ability-appropriate pursuits. Especially when you've admitted that you have disc issues that may impair your lower limb function ie the ability to move your feet quickly from accelerator to brake.
http://www.australianfrequentflyer....flying-emirates-start-training-now-70245.html
Also I would recommend that you see your GP, because perhaps you need different medication and a cardiovascular review, rather than high doses of caffeine and its attendant risks/side-effects.
If this wasn't an anonymous forum, I'd be obligated to report you to the state Transport/Driving License authority.
Otherwise, good troll! I love how you fit the stereotypical grumpy-old-man role perfectly!