If I was in desperate need I'd work 7 days a week, 12 hours a day, and do all sorts of questionable shit. Including those random medical tests.
Haha seriously? no way I would ever even consider taking part in paid clinical trials to get out of a money jam, the moment you sign that consent form you basically turn into a lab rat
Plus you could end up with health complications costing you even more money. You'd be better off working your ass off with 2 jobs for 18 hours a day. That's one thing that we should never sacrifice ever, our health... If you are still healthy you could earn more and you could pay your debts... I think I'll agree with working on many jobs in a day as long as you can handle it.. The more jobs you have the lesser the chance that you'll have a problem with money... Just make sure to take a rest if you are feeling uncomfortable due to fatigue...
As long as you could able to handle the jobs without risking your health then you should proceed. As you mentioned you would have lesser problems regarding on money since you could actually able to save it because of the jobs you have.