It has been shown in some studies that taking Prozac (fluoxetine) after MDMA use (4-6 hours after your dose) does some good at preventing neurotoxicity and 'comedown' effects / serotonin depletion. I think this has led to a false belief amongst the MDMA community that any SSRI will help with comedowns.
This is because there's a theory that neurotoxicity comes from dopamine uptake into serotonin axons as the MDMA wears off, but as MDMA has been injected directly into brains at high doses without any signs of neurotoxicity, while this uptake process still occurs, it's unlikely. A more likely theory is that the MDMA dose you swallow is metabolised partially into MDA, which itself is metabolised further into a couple of known neurotoxins. Prozac inhibits quite strongly the enzyme which breaks the MDMA down in to MDA, and therefore this seems like why taking Prozac prevents neurotoxicity from MDMA. There may be other SSRIs or even other substances completely (grapefruit juice is one) that can do the same enzyme inhibition, but seeing as Prozac has been the only one studied formally I'd try and get your girlfriend to stick to that, as IMO SSRIs are funny things and probably ones that you'd be best not having in your system unless you're absolutely sure you want them there. Be aware that you should only take the Prozac 4-6 hours after dosing as it will kill the roll, it also may kill any after glow you get while coming down, this is due to its SSRI effects. I don't keep links to studies on hand but if you google this I'm sure it won't be too hard to find.
Even if the metabolite theory is totally false, Prozac DOES help mitigate MDMA neurotoxicity, and Zoloft may well not, so it's still worth noting.
