So heres the scoop...
Ive just been prescribed Celexa (citalopram), and I have a drug interaction question.
To those of you who have been on Celexa or a similar SSRI, what are your experiences with opioids or any other substances interfering with the drug?
I also smoke weed everyday but I doubt that would pose a life threatening problem
So thoughts? comments? concerns?

Thanks.
Assuming your taking your standard opiates (hydrocodone, oxycodone, morphine, codeine, etc) and not something like tramadol, there shouldn't be any terrible interactions between your Celexa and opiates.
However, some opiates (like tramadol) can cause some pretty nasty things if mixed with SSRIs. Including but not limited to: serotonin toxicity, lowered threshold for convulsions (much more likely to have a seizure), increased body temp, and even death.
I went through a little tramadol stage at one point, and I was on 150mg of Effexor. I would take 200mg of tramadol as a standard dose and I survived without much side effects, but EVERYONE IS DIFFERENT, and what didn't hurt me might hurt you.
As for other drug interactions that can happen with Celexa (just in case you weren't aware):
-MDMA will not effect you at all. There might be a mild stimulant effect, but for the most part you will not feel anything from MDMA.
-Amphetamines/Cocaine/Stimulants should be relatively unaffected and can be used safely, however some people report a longer amphetamine duration while on SSRIs, and people also report less of a "lovely empathetic" feeling from stimulants while on SSRIs.
-LSD/Mushrooms will be dulled down a little bit in effects. I'm not exactly sure why, but SSRIs significantly lower the effects of LSD/Mushrooms and other 5-HT2a psychedelics.
-Alcohol might be more sedating, and combining alcohol with SSRIs will be an extra load on your liver which could cause some damage.
-Benzodiazepines have pretty much no negative interactions with SSRIs, and they are actually quite commonly used in conjunction with SSRI treatment to get rid of the onset anxiety of the first few weeks of SSRI treatment.
-DXM with an SSRI can cause serotonin syndrome, and can be life-threatening. I used to take DXM while I was on 150mg of effexor, and I lived. But I was potentially playing Russian Roulette with chemicals. The effects were a lot stronger and uncomfortable.
I know that's probably more info than what you asked for, but just in case someone who uses the search engine or someone from google happens to wander in here (a lot of people probably search "SSRIs and drugs"), then this information might be useful.