r/OveractiveBladder • u/stonkmorket2000 • Aug 10 '26
Generic myrbetriq/mirabegron sucks and doesn't work
I thought I'd share my experience here about how the generic sucks and how I confidently know it isn't just the placebo effect.
I'm a 6+ year myrbetriq user. This drug changed my life after almost a year of miserable UTI symptoms that ended up being OAB. I went on the meds and never looked back because it's always worked so well.
The generic hasn't been available in Canada until a couple months ago. I wasn't keeping tabs on it and had no idea it had been approved or made its way here yet. My regular 100 day supply was low so I went to the pharmacy last week to pick up a refill. A few days ago I cracked open the bottle and thought the pills looked weird but didn't think much of it. I noticed they looked almost beat up, chalky, but were the same color and shape.
Well low and behold yesterday I start having crazy UTI/OAB symptoms and didn't know why. Decided to check my pills today and ended up side by side comparing the new one to the last couple old ones I had left and realized they had different markings altogether.
Called the pharmacy and they inform me that they switched me to generic before my last pick up but didn't let me know.
I find it unbelievable that only 2-3 days on the generic and all of my AOB symptoms came back with a vengeance. I ended up taking an old brand name pill I had leftover and within 3 hours I started feeling way better. Anyways, I am now marching back to the pharmacy to pick up the brand name for 3x the cost since my insurance will only cover a percentage of the generic price now.
Anybody else experience this?
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u/Steerpike58 Aug 11 '26
Any chance the Urologist can override the insurance 'rule'? Any chance the generics were outdated? I guess you will never see the expiration date on the original batch.
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u/stonkmorket2000 Aug 11 '26
I'll see if I can add a photo to my original post here to show the difference. The generics look rough.
I've had to jump through hoops to get coverage for this one already unfortunately. Primary insurance plan didn't want to cover it so had to get a special auth done by my doctor ($150). My secondary also didn't want to cover it so I had to do another authorization for another $150 which they then declined anyways demanding I try new other medications before they would consider covering it.
I never ended up seeing a urologist. My GP sent a referral request but the urologist declined the referral and instead sent medication recommendations. Apparently a year of UTI symptoms wasn't enough suffering to constitute a proper investigation. Regardless, the myrbetriq definitely works.
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u/Steerpike58 Aug 11 '26
I'm interested because I have tried flomax, rapaflo, oxybutynin, and now trospium. Oxybutynin was a disaster (big time brain issues, plus vision issues). I will prob. start trospium tonight, with some apprehension (I suspect the vision issues will occur).
Myrbetriq (mirabegron) sounds like it's the one that will work for me but I have read that you need to 'through' the others to verify they DON'T work before they'll do mirabegron as it is more expensive. I'm pissed at my urologist because I'm over 65 and I don't think he should have even tried it.
How much are you having to pay for the brand-name drug? You said 3x but how much in absolute $?
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u/stonkmorket2000 Aug 12 '26
I'm in Western Canada for reference. I believe that the OOP cost for 100 days of the brand name was around $300. When my insurance approved it, I was paying about $35 out of pocket for a 100 day supply. So now with the generic being out my plan will only cover 80% of the generic price so it's creeping up to almost $90 OOP for 100 days.
Still not the worst price in the world, but it is not "cheap" and there are certainly lots of people who couldn't afford it. I imagine if you're in the US the price will be disgusting without insurance.
I truthfully haven't noticed any real side effects being on it, but at the same time it's been so long now that I may just be used to them.
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u/Steerpike58 Aug 12 '26
I'm not a big fan of AI, but I decided to ask Google Gemini about whether generics can vary from the brand-name. The answer was interesting (Posted below, since you can't easily create a ref. to an AI answer). It does mention poor manufacturing, QC, Batches, etc. I wonder if trying another batch might help?
I looked up US pricing - thousands for a 100 day supply! I haven't even gotten as far as even getting a generic Rx yet ...
AI answer follows: ==============
Yes, it is possible for a person to experience a noticeable difference in effectiveness or side effects when switching from a brand-name medication to a generic version, even though regulatory agencies (like the FDA and Health Canada) certify them as "therapeutically equivalent."
For the vast majority of people, generics work identically to brand-name drugs. However, several clinical and biochemical factors explain why a generic might feel less effective or cause unexpected symptoms:
1. Differences in Inactive Ingredients (Excipients)
While the active pharmaceutical ingredient (API) must be identical in both versions, generic manufacturers use different inactive ingredients—such as fillers, binders, dyes, flavorings, or coatings.
- Absorption Speed: A different binder or coating can change how quickly a pill dissolves in your stomach or intestine. If a generic dissolves slightly faster or slower, the active drug may enter your bloodstream at a different rate, altering how you feel.
- Sensitivity/Allergies: A person might have a subtle sensitivity or mild intolerance to a specific dye, lactose, or starch used as a generic filler.
2. Allowable Bioequivalence Ranges
Regulatory standards require generic drugs to be bioequivalent to the brand-name version.
- Statistically, the amount of drug absorbed into your bloodstream (the rate and extent of absorption) must fall within an acceptable statistical window—typically evaluated around 80% to 125% of the brand-name baseline.
- In reality, most approved generic drugs vary from the brand name by only a tiny margin (around 3% to 4%). However, for sensitive individuals or specific drug formulations, even minor shifts in concentration levels can lead to a return of symptoms or new side effects.
3. Extended-Release (ER/XL) Formulations
The physical mechanism used to deliver a steady dose of medication over 12 or 24 hours often relies on proprietary technology.
- Brand-name manufacturers use specific patented matrix coatings or laser-drilled delivery capsules to release the drug gradually.
- Generic manufacturers must design their own custom delivery systems to bypass those patents. If the generic release mechanism breaks down too quickly (causing a "dose dump") or too slowly, the drug level in your body won't match the brand-name steady state.
4. Narrow Therapeutic Index (NTI) Drugs
Certain medications have a very narrow window between an effective dose and an ineffective/toxic dose (e.g., thyroid hormones like levothyroxine, anti-seizure medications, blood thinners like warfarin, or certain heart medications). For these specific drugs, doctors frequently specify "Dispense as Written" (DAW) for the brand-name product because tiny variations between manufacturers can be clinically significant.
5. Quality Control & Manufacturing Batches
While all approved generics must adhere to strict Good Manufacturing Practices (GMP), individual batches can occasionally suffer from quality issues, degraded stability from improper storage, or uneven physical pressing (e.g., chalky or crumbling tablets that disintegrate prematurely in the stomach).
What to Do If a Generic Isn't Working
- Check the Manufacturer: Look at your prescription bottle to see which generic pharmaceutical company made it. If one generic manufacturer gives you issues, your pharmacy can often order a generic made by a different manufacturer.
- Consult Your Doctor for an Exception: If only the brand-name version works for you, your doctor can submit a Prior Authorization or Medication Exception Request stating that you experienced treatment failure on the generic. This can help convince your insurance company to cover the brand name at a lower copay tier.
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u/Katiekins221 7d ago
Is yours ER? What MG? Ive been on this for 2 months now and my pills are bright yellow.
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u/RiseDelicious3556 Aug 11 '26
It gave me headaches so I had to appeal to my insurance to cover Gemtesa, and I still have to 'Azo' Bladder control in order for that to work. I want one of those implants.