Stacking Question: Similar-But-Different Effects From Similar-But-Different Sources

[Fax Celestis]

If I manifest prevenom (http://www.d20srd.org/srd/psionic/powers/prevenom.htm) and then truevenom (http://www.d20srd.org/srd/psionic/powers/truevenom.htm), what happens?

[The Dark Fiddler]

What happens when you put poison on an already poisoned weapon?

[tyckspoon]

Damage stacks, so that's not a problem, and as far as I know there's nothing that says poisons conflict with each other- you could even put multiple instances of Prevenom or Truevenom on your weapon for a real big burst opener strike. If physically applying poison, the only problem would be the potential for wiping off the old poison in the process of applying the new one. Which I don't think there are actual rules for, so you're getting into Check With Your DM territory and hope he doesn't think it's terribly cheesy (alternately, you can use some of the 'this weapon makes poison/is poison/ has an internal poison reservoir' enhancements and modifications to have a dose pre-applied and then generate another one as you strike.)

[Fax Celestis]

Well, my DM has already ruled that I can use prevenom weapon with a bow, because it applies to the weapon, and ranged weapons bestow their properties to their missiles. Which both has precedent and has the same net effect as a regular weapon using prevenom weapon, despite having some logistical incongruities.