Flomax side effects

Posted by lifutang @lifutang, Jun 18, 2025

During proton therapy for prostate cancer, I took Flomax to address urinary issues. However, I experienced headache, dizziness, low blood pressure, and even fainted after standing up from a sitting position. I would like to ask if any fellow patients have helpful suggestions for managing these side effects of this medication.

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Profile picture for brian5837 @brian5837

Question: Has the Cialis helped with having to get up multiple times during the night? I never got up before Proton treatment and now I'm up 2-3 times a night. R/O wanted to prescribe Flomax but I refused for now and from what I read on this site, it doesn't help with what I want it to help. So he prescribed Cialis for the dual purpose of helping with urination and hopefully erections but I haven't started it yet. Just completed Orgovyx regimen two weeks ago. Thanks.

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I’m on Orgovyx for another 17 months and hope eventually to get back to sex. That’s the purpose of daily Tadalafil/Cialis, but it’s private pay due to lack of Medicare approval. It seems Flomax has mostly maxed my nighttime urinations to 4.

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@brian5837
I am in the same situation as you regarding Cialis. I however did not take any hormone treatments as my Decipher came back as low risk and the treatment recommendation for radiation and hormone was changed to radiation only.

When I did my 2 year follow up after radiation treatments with my R/O I went over my increased urination and that had trouble holding it if urge was high and would dribble. I was prescribed Cialis.

I filled the prescription but decided to wait to talk to my PCP to go over in depth the use of the Cialis. I was told it is prescribed a lot for urnination issues as it relaxes the bladder, urinary tract etc. My PCP asked me how much my drippling and trouble holding urgency was affecting my life style. I said was doing thing to minimalize the issues. He guidance to me was take if you feel will help or stay with your changes you have made.

Have not tried it yet. I read @brian5837 post. @brian5837 if you do try the Cialis can you post if it helped. If I decide to take in will do same.

For those taking Cialis for urniation problems would like to hear if helped or did not help.

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Profile picture for jc76 @jc76

@brian5837
I am in the same situation as you regarding Cialis. I however did not take any hormone treatments as my Decipher came back as low risk and the treatment recommendation for radiation and hormone was changed to radiation only.

When I did my 2 year follow up after radiation treatments with my R/O I went over my increased urination and that had trouble holding it if urge was high and would dribble. I was prescribed Cialis.

I filled the prescription but decided to wait to talk to my PCP to go over in depth the use of the Cialis. I was told it is prescribed a lot for urnination issues as it relaxes the bladder, urinary tract etc. My PCP asked me how much my drippling and trouble holding urgency was affecting my life style. I said was doing thing to minimalize the issues. He guidance to me was take if you feel will help or stay with your changes you have made.

Have not tried it yet. I read @brian5837 post. @brian5837 if you do try the Cialis can you post if it helped. If I decide to take in will do same.

For those taking Cialis for urniation problems would like to hear if helped or did not help.

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JC, will do. My R/O told me it will take 3-6 months for the testosterone to recover and not try sex until I notice I've regained libido and maybe nighttime erections ( I wish!) so it may be a while before I try the Cialis but will let you know its effects when I do.

Separately, I'm noticing that gas often prompts me to want to urinate and my latest theory is that if I can control the gas the urination will improve. Took Gas-X last night an hour or so before bed and only woke up once during the night around 5 a.m. Too small a sample but FWIW that's where I am. Best to you.

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I found Flomax helped me urinate during and after photon radiation. Once I finished radiation I was taking Flomax twice a day and it helped me clear my bladder. After a month I went down to one pill a day, and a month later stopped taking the drug completely. I don't have issues emptying my bladder now. No issues with urgency. I ordered 10 mg of Cialis on line to help fight future ED. I am not experiencing ED now, but it makes sense to be proactive. Unfortunately the heartburn I got from the Cialis was prohibitive and I stopped. My Dr. was reluctant to prescribe Cialis to me probably because of taking Flomax, blood pressure meds, and Cialis together could be too much for dropping blood pressure., so I ordered it myself online to try it. I can get light headed when I have a drink or two with the meds, but it goes away fast. My experience with FLomax was positive, with Cialis negative.

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Yes, I take 1 capsule daily and have experienced the exact same side effects that you are having. First you need to rise from a sitting position ever so slowly with a support device in anticipation of these effects- move along the walls of your dwelling for additional support, have in place a chair or anything you can use for your walking trip as you may need to sit down if you are starting to feel faint

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Profile picture for edtrucks @edtrucks

I found Flomax helped me urinate during and after photon radiation. Once I finished radiation I was taking Flomax twice a day and it helped me clear my bladder. After a month I went down to one pill a day, and a month later stopped taking the drug completely. I don't have issues emptying my bladder now. No issues with urgency. I ordered 10 mg of Cialis on line to help fight future ED. I am not experiencing ED now, but it makes sense to be proactive. Unfortunately the heartburn I got from the Cialis was prohibitive and I stopped. My Dr. was reluctant to prescribe Cialis to me probably because of taking Flomax, blood pressure meds, and Cialis together could be too much for dropping blood pressure., so I ordered it myself online to try it. I can get light headed when I have a drink or two with the meds, but it goes away fast. My experience with FLomax was positive, with Cialis negative.

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My experience with Flowmax is almost exactly the same. During RT (proton) I was having trouble peeing, especially at night. Started one Flowmax a day and didn't do much. Increased to two day and that was petty good. Stayed on that until about a month after RT ended went back to one a day. Urination is good both day and night. I finish ADT tomorrow and will probably try to of off the Flowmax in a couple weeks. I have zero side effects with Flowmax. My blood pressure went down 5 - 10 points systolic, but it wasn't that high to begin with and it hasn't caused any dizziness or other issues.

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Profile picture for edtrucks @edtrucks

I found Flomax helped me urinate during and after photon radiation. Once I finished radiation I was taking Flomax twice a day and it helped me clear my bladder. After a month I went down to one pill a day, and a month later stopped taking the drug completely. I don't have issues emptying my bladder now. No issues with urgency. I ordered 10 mg of Cialis on line to help fight future ED. I am not experiencing ED now, but it makes sense to be proactive. Unfortunately the heartburn I got from the Cialis was prohibitive and I stopped. My Dr. was reluctant to prescribe Cialis to me probably because of taking Flomax, blood pressure meds, and Cialis together could be too much for dropping blood pressure., so I ordered it myself online to try it. I can get light headed when I have a drink or two with the meds, but it goes away fast. My experience with FLomax was positive, with Cialis negative.

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My daily Cialis is 5mg, intended to make sexual function more recoverable when hormone therapy ends. I haven’t recognized side effects at this dosage.

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I wouldn’t dismiss Floemax. I have been on it for 3 months with great success. I started out with a UTI and PSA of 7.8 and a base from 6months prior of .6 PSA
After antibiotics to clear up UTI I was up 8-10 times a night to urinate so was given Floemax once a day, this helped some but was still up 5-8 times with difficulty even passing urine. Urologist doubled dose and made 3 month follow up appointment. The double dose did the trick I get up 0-1 per night occasionally 2. I do have slight leakage at times but that’s far better than no sleep. Only get a little dizzy going from a squat to stand. So I give it an A. Question though my urologist only did an ultrasound to see how full bladder was and not sure if he viewed CT my MD ordered or not. About 6 weeks after all this my PSA was 2.6 what should I be asking urologist on follow up????

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