When torturing people or executing them in slow and painful ways, your victims sometimes fall unconscious, which ruins the point of the exercise. After all, if they aren't feeling the pain, then what is the point of torturing them or having them boiled alive instead of just shooting them? Because of this, torturers may want to have access to drugs that can keep their victims awake for longer, so they can make their torture more intense. Do any such drugs exist? Would they be stimulants of some sort? Could smelling salts be used for this purpose?
Real-world torture is usually not as "intense" - in the sense of raw physical pain - as you might think. Torture is usually "intense" in a psychological sense. Here are a few examples (CONTENT WARNING):
- We Can Make You Talk: Interrogation Techniques. This really is a fantastic documentary on interrogation techniques - not only does it talk about the history of them, but is intermingled with experiments from a group of (willing participant) citizens. Note that no physical torture was commenced, yet all but one participant gave up the information - knowing it was a fake interrogation.
- CIA 'torture': Inside the 'blackout box' - BBC News. A reporter is placed in a blackout box (a small box with no lights in it), and sounds of a shrieking baby are blasted. She didn't last long.
What's interesting to see here is how intense physical pain is not required. In fact, intense physical pain is often the thing that makes people "check out" mentally. It's solitary confinement, black boxes, being forced to sit in awkward positions, hearing people cry, et cetera - it's these things that are the worst torture. Because it's almost impossible to tone them out.
Everyone has a breaking point, and these techniques will get you there.
Whips, electrical shocks, water boarding, and so on - these things may be effective, but not as effective as a simple black box. Also keep in mind the one doing the torture. Your arm will eventually get tired of punching someone. You won't run out of steam while sipping a tea and reading a book next to a box.
If you really want to keep someone awake with drugs, @JRams mentions stimulants and amphetamines. These would help keep you awake, but a known side effect is the reduction of pain and, in high doses, a sense of euphoria. A better bet is would be simple speed - it keeps you up and heightens focus. Back in the MKULTRA days, LSD was used in torture experiments. LSD can give you a "good" high, but it was found that prefacing the "patient" in a bad situation enhanced the opportunity of a "bad" high - meaning that it would both keep you awake and make the torture way worse by making you see things that don't exist.
Again, drugs have their limits; you can only be high for so long before dying. You can be kept alive and awake in a blackbox through simple sound for days or even weeks. The psychological effect of "normal" torture mechanisms is way worse than what drugs can give you for the simple reason that they don't have to stop. You can be under 24/7 torture for months or even years. You can't be drugged for that long. If you know that this torture might go on indefinitely, then you're more likely to break. If you think they're giving you drugs that will kill you, all you have to do is last until you die in a few days. What's worse - "this is going to end soon", or "it's possible this never ends"?
Anyway, all that to say if you're trying to heighten the "torture experience", so to speak, don't use drugs and don't be gruesome. Stick to the stuff the torturer(s) can keep doing ad infinitum, and focus on the psychological torture, not the physical torture.
You would basically need to be a medic as well as a torturer to maximise the torturing.
Using Drugs like ephedrine and amphetamines to keep them awake whilst also superficially healing their wounds for more torture later, including keeping a defibrillator at hand if necessary.
There is a vast number of stimulates that could be used with their own side effects to help with the torturing but I believe Amphetamine or ephedrine will be the best options.
What's the purpose of the torture is it to get something out of someone or to actually hurt then cause them the most pain. As someone said if its getting information sensory deprivation is a good one blind fold them stick then in a closet and play death metal as loud as possible for DAYS on end. When someone is tired there ability to lie is weakened. Another way beyond even torture is brain scans. When you lie a part of the brain lights up. So hook them up to a brain scan and ask them questions. If they lie the machine will litturally tell you. Now this does not infact work with half truths cause well must the truth. If it actually is to cause pain then falling asleep wont matter to the torturer cause the victim knows that once they wake they are in for more pain. Another way to add even more pain is fear. Have them tell them what their about to do in great detail and only do a little of it a little at a time. As that one songs goes "Antisipation..." Lastly make them make an impossible choice. Where they have no choice but they do. To "Escape" someone they know will die. Make them choose between a bunch of innocent people or someone they love and if they dont chose they both die. Sometime the guilt we put on ourselves can be torture in and of its self.