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Hot flash reduction with oxybutynin
This information came from Rick Davis in the weekly ancan.org newsletter. It’s really worth signing up for just the newsletters. I will be posting a second really informative post from Rick..
Oxy back in heat of the limelight oxybutynin
Old Dog: New Tricks JCO March 26, 2026 an Editorial by AnCan favorite, Dr. Alicia Morgans et al raises a topic addressed in our Reminder for the Jan 19, 2026 meeting - oxybutynin as an antidote to hot flashes. Ironically, just a few days after that, Dr. Brad Stish published his Alliance trial in JCO that offered a definitive correction.
Bottom line - based on Dr. Stish's Mayo trial of 80 men, oxybutynin achieved great results using oxy to reduce hot flashes for men on hormone therapy. Depending on the dose, up to 80% of men experienced a 50% reduction.
Here's the important piece of information revealed in Dr. Stish's article that was unclear in the published abstract and clinical trial information. Of the 80 trial participants only 24 (30%) were on doublet therapy with abiraterone + ADT. The remainder were all on singlet ADT alone. The lutamide Brothers were excluded.
That doesn't mean oxy only works with abi. We know it works with apalutamide from the experience of our Canadian AnCan'r who tried it with success. The dosage required with apalutamide. darolutamide or enzalutamide may be lower because of interference from the CYP3A4 pathway. Oxy has significant side effects laid out in our earlier post and below, so this should be taken seriously.
From hereon out, we can advise our Gents on ADT alone to discuss oxybutynin with their Providers. If you're on doublet with abi, we know it works; if you're on doublet with an lutamide Brother, it works but the dose is unclear.
Not published was whether including the abi changed the results.
In follow up correspondence with Dr. Morgans, she mentions that her clinic has prescribed oxy for all ARSI with around 40-50% success. While her editorial referenced estradiol (E2), making our Emperors smile no doubt, it failed to mention that supplementary E2 may address hot sweats.
And in deference to Dr. Paul, and Dr. John, who always considers Adverse events, we're obliged to mention that oxy can cause dry mouth, constipation and occasional urinary retention. Nothing comes without a cost!
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sounds like the side effects are worse than the hot flashes..I just got an Rx for Gabapentin ..but after reading its side effects ( which are similar to oxybutynin )..I dont think I will pick it up..anyone have any exp with either of these ??
I was thinking of just taking a small doses every other day to see if it reduced hot flash with minimal side effects..
@xahnegrey40
I take 600 mg of gabapentin Three times a day. No Side effects really, Though you do have to taper off if cutting back or quitting.
I don’t really notice it doing anything for my hot flashes. I was taking it when I had really severe ones and I still have 4 or more a day.
@jeffmarc so why do you take it if it doesnt reduce hot flashes and intensity ??..my hot flashes are not bad during the day, but a bit depressing at night//when I get up to pee, I know a hot flash is coming on shortly..
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1 ReactionThere were two links in this article, but for some reason, they did not come over as links so here they are
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@xahnegrey40
My oncologist prescribed a depo-provera Shot every three months. It’s a birth control for women, but it doesn’t cause breast enlargement and men. It kept my hot flashes down to almost nothing until I went on Zytiga, Then they came back pretty strong.
When I got the Embrlabs.com Wave device It stopped my night sweats and hot flashes. During the day it wasn’t as effective when they were really severe. Had to hit the button on the device really early in the hot flash to do any good.
A few months ago, at the Mayo Clinic monthly meeting the doctor posted this list of drugs to hop manage hot flashes.
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2 ReactionsThanks, Jeff! I just subscribed to ancan.org. I am taking 5mg Oxybutynin 2X daily, and I would agree with the study results that I have 50% (or more) reduction in severity and frequency of hot flashes. I'm still up about 4X nightly to urinate, and my urologist has added (at my suggestion) .4 mg Tamsulosin nightly which I've only taken for about a week so may have more to report later. I do experience dry mouth but don't seem to have any issue with constipation or brain fog. As I'm writing on April 5, Happy Easter to all!
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2 ReactionsOxybutynin saved my sanity. About 6 months after IMRT my bladder control was depressingly terrible. I had to pee very frequently and holding it was never an option. I learned the hard way if I felt the need to pee I had to Go Right Now. I bought a large supply of pads an flying internationally was not a fun experience.
I had a Radiology doctor appointment the day before a flight to Vegas and when I brought it up she prescribed Oxy and it literally fixed me overnight. Out of fear and recent experience, I wore a pad every day of the trip, didn't have an issue, and the pads are sitting unused in my basement since my return.
When I mentioned this to my urologist he was happy for me but told me to get off it as soon as I could because it would make me... and he imitated the look of someone I didn't want to be. I got myself off it a few weeks later without any issue and without a return to pad life.
My hot flashes went away with Gabapentin, a neck fan (especially after a hot shower), and then by themselves about 9 months after radiation. I didn't notice any particular change in them when I was taking both and I gave up Gab shortly after I said goodbye to my friend Oxy.
I just took delivery of my last bottle of Abiraterone! Where's the bell for that!
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2 ReactionsI take 200mg Gabapentin nightly and it has almost eliminated my nightly hot flashes with no apparent side effects.👍 However, having only one alcoholic beverage even 5 hrs before bedtime negates the benefits.
No booze, no sex. Not fun.
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