Ironically, while selegiline can't be mixed with cheese or Prozac, it can be mixed with methamphetamine and cocaine. A small placebo controlled study found that concomittant administration of methamphetamine (15 or 30mg) with selegiline (oral) caused no EKG, lab, or vital sign changes. The clearance and half-life of methamphetamine was also unchanged. Similarly, 10mg PO can be safely mixed with up to 40mg cocaine, should you be into that. An earlier study found that 10mg/d could reduce the high of cocaine and reduced the activity of the amygdala (as defined as glucose utilization on PET scan) and not caus any negative interactions.
If that's not good enough for you, a study using the selegiline patch 20mg/d in 12 cocaine addicts found that heart rate and blood pressure were lower on selegiline at baseline, and were increased less after 40mg cocaine IV. It caused a slightly less subjective feeling of highness. In case this is not amazing to you, let me point out that as an MAO-B inhibitor, selegiline should increase dopamine levels-- and you should feel more high. But the opposite happened. (Why? Because selegiline already raises dopamine, so the effect of cocaine is less (because there's less dopamine left to increase) and so it feels less fun?)
It had no effect on cocaine pharmcokinetics or dynamics, and did not alter cocaine's effect on prolactin (suppression) or growth hormone (increase.)
A larger, 300 person double blind trial of patch versus placebo (done by the same authors) found no difference for the treatment of cocaine dependence-- but, importantly, there weren't any adverse effects of mixing the two, either.
While not recommended, it appears the patch is at least safe with your addict populations.