Cooper brought Benzedrine onboard to keep the pilots awake. Described in Gray's SKYJACK, and the 302s floating around.
No one knows if or what medications Cooper took, as far as I know. The CS have speculated that it could have been blood pressure medication because that is the most widely prescribed med in the world, and the coatings of those pills often have a powdery mix of Lycopodium, which was found on the tie.
I discuss this in my book, and also the related issue of amphetamines in combat and for flying. The use of amphetamines and methamphetamine was first widely used by Japanese pilots in WW II, and copied by all Allied forces as well. But their use in Vietnam by US Forces exceeded the combined prior worldwide usage.
The essential question still remains: did Cooper use drugs or any other enhancements? Amphetamines and other pharmaceuticals could have helped him stay warm, stay awake and alert, reduce hunger, reduce pain from injury, etc. It is rarely talked about, nor investigated. - most probably because most people think of DB Cooper as a guy like them or someone they know, and few people regularly carry these kinds of drugs, have access to them, or even know about them.
But a commando would, I say.