Risperdal and Prozac Drug Interactions?

So I have been on risperidone and prozac since the fall of 2008. Nothing "bad" has happened to me on either of them.

I was bored today and came across some sites that list drug interaction risks on them. Most I came across list the two I am on as a moderate risk, 2 listed it was a severe risk. ?????

Does anyone know if the information I came across is reliable? I haven't had any negative reactions taking them together, so should I worry?

My old pdoc is the one who originally prescribed the combo, then I changed pdocs due to moving and the new pdoc agreed with the meds and originally kept them the same (just recently increased them).

Are there "bad" reactions between risperidone and prozac?

They both use the same enzyme for metabolism, which means that you would need to take lower doses of one or both drugs. What dose of risperdal are you on?

P.S. for questions like these, it's always best to ask your pharmacist. They generally know more about drug interactions than doctors do.

I am on 3mg of Risperdal a day (1mg in the morning, 2mg at bedtime) and just increased to 40mg of Prozac in the morning a week and a half ago (previous prozac dose was 20mg).

Never thought a pharmacist would know more about interactions than a doctor, but now that you said it, it makes sense.

Seriously, we have learned so little pharmacology in med school that it is truly embarrassing. We have had maybe like 2 lectures on pure pharmacology. We learn a lot about which drugs to use for which conditions, what the drugs do, the mechanism of action, and side effects. But the underlying pharmacology? Like which enzymes metabolize which drugs? Drug interactions? That kind of stuff? Nada. We don't learn ANY of that. But pharmacists spend a lot of time learning about the metabolism of different drugs, enzyme kinetics, and drug interactions.

Just called a different Walgreens than I use (since the pharmacy at the one I normally use is already closed) and they said I shouldn't take both of these drugs together and need to call my doctor ASAP and get one changed. Think she may have been overly cautious, if it was really that "dangerous" wouldn't they have caught it when I filled them?

Also tried the pharmacy chat online at Walgreens.com, they said soemthing different. They said as long as I space them out in the morning I will be fine (ex. take risperisdone at 7am and prozac at noon or take the prozac at 7am and risperidone at 10am). How would I get two different answers? Does this answer seem reasonable?

Will try calling my Walgreens tomorrow and see what they say. I mean I have been taking both since 2008 and am still alive, so I don't think it is as dangerous as the one pharmacist was making it out to be.

I'm not too worried...just more curious now as to which answer is more creditable.

Honestly if you've been on both meds since 2008 and haven't had any problems, I wouldn't worry about it. If you were going to have a bad interaction odds are you would have had it by now.

Drug trial results are required to list every possible side effect / interaction even if relatively few people experience it. When I started on risperidone, my pdoc told me not to be freaked out by the list of possible side effects listed on the patient handout. When I got the patient handout at the pharmacy I freaked, but I've had minimal side effects from the drug and I've been on it since 2005.

I think what pharmacists tell you will vary by pharmacist too and their own level of knowledge. I know for a fact, for example, that risperidone can cause bone density to decrease, but when I asked a pharmacist about it she flat out said it wasn't a side effect. I also heard the same pharmacist tell another patient that seroquel was a sedative, not that it was an anti-psychotic. Sorry another pet peeve of mine is seroquel overprescribing. Sorry didn't mean to hijack your thread

splitimage

I was on both meds for nearly 2yrs. I never experienced adverse reactions to the combo. That being said tho, I was on much lower dosages than you. 1mg Risperdal, split into 2 doses to decrease sedation, and 20mg Prozac. (40mg during depressive episodes).
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The Risperdal was added whilst inpatient, so I'm sure they did their homework. I do believe however that the dosages could possibly affect interaction, and that's might be why some professionals advise against the combo.

Just tried calling another 24 hour Walgreens they said it's common for both to be prescribed together and that it only shows as a reaction because seritonin syndrome could occur which mean the fluoxetine would be stronger. Basically told me there is nothing to worry about and it's safe to take both together. Looks like the one pharmacist was overly careful.

When I looked it up it said that both can prolong the QT interval. But, so many drugs that prolong the QT interval are prescribed together!

In general, I think it's good to find a very knowledgeable pharmacist that you trust. My pharmacist has a PhD in pharmacy and is a professor at the local pharmacy school. To find a good pharmacist like that, go to the website of the local pharmacy school in your area (if you have one) and look at the list of teaching faculty. Many of the faculty will have their own pharmacies. These pharmacists will be the cream of the crop.

I'm on meds that interact too, seroquel and wellbutrin. Low low dosage of seroquel so, interaction isn't a worry. Dosages are important!

What's the QT interval? I've never heard of it.

It has something to do with the heart. Here's a wikipedia article on it:
http://en.wikipedia.org/wiki/QT_interval