Starting Prozac for maybe 5th time. Feeling breathless

[Deepseathree]

Feelings of shortness of breath

As the title says I’ve got a feeling of shortness of breath. My O2 and heart rate seem to be fine for the most part, it’s just the feeling of needing to take a deep breath.

I’ve been on and off Prozac almost 5 times. I just started back up a couple weeks ago. I’ve never had this problem before though.

Just seeing if anyone else has experienced this and what the outcome was.

[panic_down_under]

As the title says I've got a feeling of shortness of breath. My O2 and heart rate seem to be fine for the most part, it's just the feeling of needing to take a deep breath.

Shortness of breath is a listed potential initial side-effect of fluoxetine and some other SSRIs. Serotonin has many roles in the brain and body including in the regulation of the breathing reflex in the brain stem which may account for what you're experiencing. But the heightened anxiety that often occurs soon after beginning to take ADs may also be a factor. Most of the initial side-effects begin to diminish as bio-feedback mechanisms kick-in to reduce serotonin synthesis and expression, however, they can linger for some.

I've been on and off Prozac almost 5 times. I just started back up a couple weeks ago. I've never had this problem before though

Side-effects may be different each time an AD is recommenced and they may also be more severe than previously too. Given you've been on fluoxetine 4 times in the past you should consider staying on it permanently from now on, imho, as there is evidence antidepressants, especially the SSRIs and some other serotonergic ADs, can become progressively less effective every time they are stopped and restarted, often requiring higher doses to achieve the previous level of control, or not working at all. Two studies, Amsterdam JD, 2016 and Amsterdam JD, 2009, found the likelihood of antidepressants working after each restart drops by between 19-25% (see also: Bosman RC, 2018; Amsterdam JD, 2009; Leykin Y, 2007; Paholpak S, 2002).

[Deepseathree]

You’re an amazing wealth of knowledge and deserve more recognition for all the effort you put in.

While I have you may I ask about QT Long Prolongation? Is that something I should worry about with Prozac and Losartan?

Also is the bradycardia associated with Prozac mean a longer qt interval?

[panic_down_under]

While I have you may I ask about QT Long Prolongation? Is that something I should worry about with Prozac and Losartan?

Probably not. A lot of meds, including, ironically, many heart medications can lengthen the QTc interval. Everything from some antibiotics to zit meds. Losartan doesn't. Fluoxetine is in the lowest catergory of QTc prolonging meds having a Conditional Risk of triggering TdP (Torsades de Pointes) which means:

These drugs are associated with TdP BUT only under certain conditions of their use (e.g. excessive dose, in patients with conditions such as hypokalemia, or when taken with interacting drugs) OR by creating conditions that facilitate or induce TdP (e.g. by inhibiting metabolism of a QT-prolonging drug or by causing an electrolyte disturbance that induces TdP).

- From CredibleMeds which maintains the data base of QTc prolonging meds for the FDA -

So when taken alone it won't prolong the QTc interval in otherwise healthy people, but it could have an additive effect if taken with meds which do, or if there is an electrolyte imbalance. Your doctor should take this into consideration when prescribing meds. It doesn't mean other meds with such a potential shouldn't also be prescribed, just that this needs to be considered when calculating the dose. When you get to my advanced years you will likely be on a number of meds with such interactions. Juggling is a necessary skill in the art of medicine.

Also is the bradycardia associated with Prozac mean a longer qt interval?

Not usually. Plus, how low is your heart rate? Until recently the normal resting heart rate range for adults was considered to be 60-100bpm, however, cardiologists are increasingly thinking it should be between 50-70 bpm. See: What is a Normal Heart Rate? and 5 Heart Rate Myths Debunked.

Fwiw, I've been on a very high dose of the most cardio toxic AD on the market, dosulepin, for about 30 years. I've also been on medication to keep my BP lower than normal to lessen the impact of a partial lung removal on the cardiovascular system for 18 years. A side-effect of this is my resting heart rate rarely gets above 52 bpm and so far the only issue has been my smart watch waking me at night when the HR drops below 48bpm.

[Deepseathree]

My heart rate has been as low as 39 one night, but that seems to be a one off event. Though I’m typically mid 40s it seems. Resting is typically 50-60s.

Could qt prolongation be a worry with starting and stopping Prozac as the side effects change the more I take it.

I had an ekg a few days ago for something separate and was already back on Prozac for about 10 days, possibly more. So I would surmise something would’ve shown up there.

I also had a stress test amongst other things earlier this year before a stopped taking it.

[panic_down_under]

My heart rate has been as low as 39 one night, but that seems to be a one off event. Though I'm typically mid 40s it seems. Resting is typically 50-60s.

If the readings are from a smart watch I wouldn't worry as they are far from reliable, but mention it to your doctor at the next consultation.

Could qt prolongation be a worry with starting and stopping Prozac as the side effects change the more I take it.

No. Don't get fixated on QT. It might, repeat might, be a factor in a very limited set of circumstances none of which seem to apply to you. SSRIs are often prescribed for heart attack survivors to treat the anxiety disorders and/or depression which many develop subsequently. SSRIs are also mild anticoagulants which can be a benefit for cardiovascular health.

I had an ekg a few days ago for something separate and was already back on Prozac for about 10 days, possibly more. So I would surmise something would've shown up there.

I also had a stress test amongst other things earlier this year before a stopped taking it.

Then you have solid evidence that fluoxetine isn't having a deleterious effect on your heart. You are at much higher risk of falling under the proverbial bus on your way to and from the pharmacy to fill the Prozac prescription than from the med itself.

[Deepseathree]

You don’t think starting and stopping it so much has changed the way it affects me and also being on Losartan with it? I’m only on 10mg of Prozac also.

[panic_down_under]

You don't think starting and stopping it so much has changed the way it affects me

It may have had some effect on your brain. Your heart, unlikely, especially not on QTc.

and also being on Losartan with it?

There is no significant drug interaction between fluoxetine and losartan, nor is there evidence that losartan affects the QTc interval.

I'm only on 10mg of Prozac also.

Do you plan on increasing the dose to at least the recommended minimum dose of 20mg? If not you should as being on potentially sub therapeutic doses for extended periods increases the risk of ADs pooping-out.