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Effexor XR and Prozac | Bridging the Two Drugs

April 4, 2012

So you’re wondering what a Prozac bridge is, right? Well, if you take Effexor XR and have been trying to wean yourself from the drug but simply can’t get below 37.5mg, 75mg, or even more than maybe the Prozac bridge is the answer. Or not. You should DEFINITELY consult with your doctor before changing the dosage of any medication. This is NOT intended to replace your doctor’s advice. I’m sharing with you what my research has yielded and I will bring my findings to discuss with my own doctor when I see her next month.


A few days ago I wrote about how I can’t stop taking Effexor XR. I’ve successfully gotten down to the lowest available time-released dosage of the medication. For a short time I was even able to get into an every-other-day regimen but currently I am taking it daily.

I’ve spent a good amount of time reading message boards and online forums from people with the same problem as mine. I came across a Q&A with Dr. James Phelps (I don’t know anything about this guy — he could be some random dude playing a doctor online — so consult with your doctor first!). He references Joseph Glenmullen’s book, Prozac Backlash and a chapter called “Held Hostage” where the author writes about the theory behind “Prozac bridging.” In the simplest terms: you replace Effexor XR with Prozac.

Now I know it sounds like you’re just replacing one med for another but there is science behind this idea and it has to do with the “half-lives” of the drug. All anti-depressants have “half-lives” and what that means is how quickly the drug leaves a person’s blood stream after you’ve taken your last dose. Effexor XR has an extremely short “half-life” which is the reason behind the horrible withdrawal symptoms. Phelps explains the details here. I also found to be a good source too in understanding “half-lives.”

So what’s Prozac have to do with it? Prozac is an extremely long “half-life.” It takes Prozac 7-9 days to leave the blood stream (as compared to Effexor XR at 15 hours). Withdrawal symptoms are considered unusual when taking Prozac. When you are able to get to the lowest dose possible on Effexor XR is when you are suppose to replace – or bridge – it with Prozac. It’s up to you and your doctor when you decide to wean from the Prozac but apparently it’s supposed to be head and tails easier to do than Effexor XR.

A couple of suggestions I received from this week’s earlier post on the subject that I thought were worth considering:

– My friend and nurse Kathleen suggested progressively lengthening the intervals. “It might be inconvenient (maybe having to set an alarm for the middle of the night), but you could make up a schedule for every 48, 50, 52 hrs, etc…? Or try taking one every 2.5 days (60 hr intervals)?” My note: I don’t know for sure if this would work considering those pesky short “half-lives.” I think lengthening the time between is just prolonging the withdrawal symptoms and then you are back at square one once you take it.

– Another friend suggested seeking help from naturopathic doctor. I’m seriously considering consulting with the specific doctor she recommended for this and possibly other issues I am experiencing (inflammation, fatigue, etc.).

– A family friend and pharmacist suggested taking the immediate release Effexor (I currently take the XR – “extended release”) which at its lowest strength is 25mg and it comes in tablet form that can be cut in half and quarters to decrease the dosage over time. The XR comes in capsule form which cannot be cut. Her thoughts on bridging Effexor and Prozac “would basically be adding a different drug that has the same mechanism of action” and “would not gain a great deal from that switch.”

I’m not exactly sure what avenue I’m going to pursue yet. I’ve really considered the white knuckle approach but I’m so worried that the side effects would last longer than three days. I’ve read some people feel sick up to a month. I really don’t want that. I’m definitely going to discuss the options with my general practitioner (as opposed to my oncologist who said I should just keep taking it). I’ll keep you posted.

This information is not to replace any advice your personal doctor has given you.  I do not make any claim that Prozac bridging works.  This is simply the research I have found.  Go talk to your doctor!