Like one poster suggested, dexedrine works well, though these days I'd say that lisdexamfetamine, brand name Vyvanse, is a better option. It's a prodrug for dexamphetamine (dexedrine), making your body has to metabolize it before it's active. That means a slow steady onset and a slow wearing off, so it doesn't produce crashes the way plain dexedrine and adderall do.

Alternatively there is modafinil/armodafinil, provigil and nuvigil. They're the same drug only the latter is a single enantiomer, so it's roughly twice the potency of provigil. The price is the biggest difference.

I'm prescribed nuvigil, and it is crazy expensive. Without insurance a bottle of thirty 150mg tablets would be 500 something. Provigil is generic more though, and not very expensive afaik.

It increases wakefulness without making people jittery. Also, while it is a controlled substance like dexedrine (though in the lowest class, where dex is in the highest highest legally prescribe-able), to date there has not been a single case of abuse or addiction published in the literature. That's pretty good considering that there are reports of benadryl addiction

one thing that needs to be considered, too, is that dexedrine is known to be neurotoxic in higher doses, and has been implicated in causing Parkinson's Disease. Not a strong association, but it may play a role in disease development for some people. It causes dopamine to be released, along with norepinephrine, which cause wakefulness.

This leads to a decrease in dopamine levels, at least temporarily.

Modafinil, however, has a very complex and not entirely understood mechanism, but it is known to inhibit the reuptake of dopamine from the synapse. This is a far more gentle process. Also, reuptake inhibitors aren't known to cause neurotoxicity.

I think it's a better drug. You could look in PubMed for info on its use in Parkinson's patients. It may be helpful, even.