Enablex vs Myrbetriq

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Introduction

For patients suffering from overactive bladder (OAB) or urinary incontinence, there are certain medications that can help control these symptoms by interacting with bladder muscle contractions. Enablex and Myrbetriq are two such drugs prescribed for these conditions. They each impact the muscles of the bladder differently, but both provide relief to patients with OAB or urinary incontinence. Enablex is classified as an antimuscarinic drug which works by relaxing the detrusor muscle that lines the bladder wall, thus reducing spontaneous contractions which can cause urgency and frequency of urination. On the other hand, Myrbetriq belongs to a class of drugs known as beta-3 adrenergic agonists; it helps relax the bladder's smooth muscles, improving its ability to store urine and minimizing instances of involuntary leakage.

What is Enablex?

Darifenacin (the generic name for Enablex) is an antimuscarinic drug approved by the FDA in 2004. It primarily targets M3 muscarinic receptors located on the smooth muscle of the bladder, reducing bladder contractions and increasing bladder capacity, which aids with issues like overactive bladder. Enablex has a selective influence on M3 receptors with only minor effects on other receptor types, resulting in fewer side effects than other drugs that have stronger effects on these different types.

Mirabegron (the brand name Myrbetriq), however, belongs to a class of drugs known as beta-3 adrenergic agonists. Approved by the FDA in 2012, Myrbetriq works differently: instead of inhibiting contraction like Enablex does, it promotes relaxation of the detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle. This results in an increase in bladder capacity without suppressing detrusor muscle contractions during voiding. The choice between these two medications will depend largely upon individual patient needs and responses to treatment.

What conditions is Enablex approved to treat?

Enablex is approved for the treatment of various urinary conditions:

Overactive bladder with symptoms of urge urinary incontinence
Urgency and frequency

Myrbetriq, on the other hand, is also used to treat overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency and urinary frequency. In addition to this, Myrbetriq can be used for treating OAB due to neurogenic detrusor overactivity (NDO), a condition often associated with multiple sclerosis or spinal cord injury.

How does Enablex help with these illnesses?

Enablex helps to manage overactive bladder by blocking the action of acetylcholine, a neurotransmitter that can increase the activity of the bladder. It works by binding to muscarinic receptors in the smooth muscle of the bladder, preventing acetylcholine from attaching and causing these muscles to contract. By reducing inappropriate contractions, Enablex can help control symptoms such as frequent urination, urgency, or incontinence.

Acetylcholine is a chemical messenger that plays many roles throughout your body including regulation of heart rate and memory formation among others. When it comes to bladder function though, inhibiting its effects results in less urgent need to urinate.

Therefore, by decreasing this excessive communication between nerves and muscles within urinary tract system with Enablex, patients can regain control over their own bladders which ultimately improves their quality of life.

What is Myrbetriq?

Myrbetriq is a brand name for mirabegron, which is a beta-3 adrenergic agonist that functions by relaxing the smooth muscle of the bladder, thus increasing its capacity to store urine and reducing the urge to urinate. It was first approved by the FDA in 2012. Unlike antimuscarinic drugs such as Enablex (darifenacin), Myrbetriq does not inhibit acetylcholine at muscarinic receptors. This difference means that side-effect profiles are distinct between these two types of medication; in particular, Myrbetriq is less likely to cause common antimuscarinic side effects such as dry mouth and constipation. The effect on bladder function can be particularly beneficial for treatment of overactive bladder symptoms, especially in patients who do not respond well or cannot tolerate typical antimuscarinic drugs such as Enablex.

What conditions is Myrbetriq approved to treat?

Myrbetriq has been approved by the FDA for treating conditions such as:

Overactive bladder (OAB) with symptoms of urgency, frequency, and urinary leakage
Neurogenic detrusor overactivity (NDO), a bladder dysfunction related to nerve damage which can result in high bladder pressures and incontinence.

How does Myrbetriq help with these illnesses?

Myrbetriq, or mirabegron, is a unique medication in managing overactive bladder symptoms. It works by activating the Beta-3 adrenergic receptors that relax the detrusor smooth muscle in the bladder wall, therefore increasing its capacity and reducing urgency and frequency of urination. Unlike antimuscarinic drugs such as Enablex which work by blocking nerve signals that cause contractions in the urinary bladder muscles, Myrbetriq does not have anticholinergic side effects (like dry mouth or constipation) due to its different mechanism of action. Hence it could be a preferred option for patients who do not respond well or experience unwanted side effects with antimuscarinic medications like Enablex. Its effect on norepinephrine may also contribute to an increase in urine storage capacity during filling phase.

How effective are both Enablex and Myrbetriq?

Both darifenacin (Enablex) and mirabegron (Myrbetriq) have established histories of success in treating patients with overactive bladder, and they were initially approved by the FDA a few years apart. Since they act on different receptors within the bladder, they may be prescribed under different circumstances. The effectiveness of darifenacin and mirabegron in alleviating symptoms of overactive bladder was directly studied in several clinical trials; both drugs exhibited similar efficacy in managing symptoms as well as similar safety profiles.

A 2005 review on darifenacin demonstrated that it is effective from the first week of treatment, that its side effect profile is favorable among many other antimuscarinic agents due to its specificity for M3 receptors which are predominantly found in the bladder, thereby reducing unwanted side effects like dry mouth and constipation. This study reports that darifenacin has become a widely prescribed drug for overactive bladder around the world.

A 2012 meta-analysis indicated that mirabegron seems to be more effective than placebo in treating an overactive bladder, demonstrating advantages such as increased urine storage capacity without slowing down urinary flow rate or causing urinary retention. Nonetheless, while Myrbetriq's unique mechanism of action makes it suitable for those who cannot tolerate anticholinergic medications or possess contraindications towards them, more robust long-term studies are required to further establish its stand-alone efficacy compared to other treatments.

abstract image of a researcher studying a bottle of drug.

At what dose is Enablex typically prescribed?

Oral dosages of Enablex typically start at 7.5 mg/day, but for some patients, a higher dose of 15 mg/day may be more effective in treating overactive bladder symptoms. It's important to note that children should not use this medication. For adults and the elderly, dosage can be increased from 7.5 mg to 15 mg after a couple of weeks if there is no response or insufficient symptom control. The maximum dosage that should not be exceeded under any circumstances is 15 mg/day.

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At what dose is Myrbetriq typically prescribed?

Myrbetriq treatment is typically initiated at a dosage of 25 mg once daily. If necessary, the dose can be increased to 50 mg/day after two weeks if the patient does not experience adequate symptom relief and side effects are tolerable. For patients with severe kidney or liver impairment, a starting dose of 25 mg every other day should be considered. It's important to remember that maximum effectiveness may not be observed until eight weeks of therapy have been completed. Myrbetriq tablets should not be chewed, divided, or crushed; they must be swallowed whole with water.

What are the most common side effects for Enablex?

Common side effects of Enablex (darifenacin) and Myrbetriq (mirabegron) are generally similar, though there are some differences. The shared side effects may include:

Dry mouth
Constipation
Headache
Nausea
Dizziness

However, with Enablex you might also experience heat exhaustion or stroke in hot weather. And while taking Myrbetriq, patients may experience increased blood pressure, urinary tract infection, common cold symptoms (rhinitis), sinusitis and diarrhea. Both medicines should be used under medical supervision and any side effects should be reported to healthcare providers immediately.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Enablex?

In rare cases, Enablex can exhibit potentially serious side effects. These include:

Any signs of an allergic reaction such as hives; difficulty breathing; swelling of your face, lips, tongue or throat.
Serious urinary tract infections with symptoms like painful urination; muscle aches and pains; feeling tired or short of breath; blood in urine.
Severe stomach pain or constipation for three days or longer
Liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools and jaundice (yellowing of the skin or eyes).

Similarly Myrbetriq also has some potential side effects which are uncommon but could be severe including:

Allergic reactions: rash/hives/itching/swelling especially around the face/tongue/throat leading to severe dizziness/difficulty breathing etc.
High blood pressure with symptoms such as headaches/confusion/blurred vision/chest pain etc
Kidney problems where you may see changes in amount/color/smell of your urine along with unusual weight gain/swelling in extremities.

If any such adverse events occur while on either medication it is important to seek immediate medical attention.

What are the most common side effects for Myrbetriq?

Myrbetriq, like all medications, can also result in certain side effects. Some of the most common ones associated with Myrbetriq include:

Increased blood pressure
Common cold-like symptoms (nasopharyngitis)
Urinary tract infection
Headache
Dizziness
Rapid heartbeat (tachycardia)
Abdominal pain It's important to note that this is not an exhaustive list and other side effects may occur. If you experience these or any unusual symptoms after taking Myrbetriq, it would be advisable to consult with your healthcare provider immediately.

Are there any potential serious side effects for Myrbetriq?

While Myrbetriq is generally well-tolerated, it may cause certain side effects in some individuals. These can include:

Signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat
High blood pressure - severe headache, pounding in your neck or ears
Dangerously high blood pressure - severe chest pain, shortness of breath, irregular heartbeats
Painful or difficult urination
Little to no urinating

If you experience any of these symptoms after taking Myrbetriq, seek immediate medical attention. It's important to note that this isn't a complete list and other side effects may occur.

Contraindications for Enablex and Myrbetriq?

Both Enablex and Myrbetriq, like most other medications for overactive bladder, may cause certain side effects. If you notice any severe or troubling symptoms such as rapid heartbeat, painful urination or inability to empty the bladder completely, please seek immediate medical attention.

Neither Enablex nor Myrbetriq should be taken if you are using any drugs that inhibit the CYP3A4 enzyme (like Ketoconazole). Always inform your healthcare provider about all the medicines you take; these types of inhibitors may increase levels of either medication in your body leading to a higher risk of adverse reactions.

Enablex and Myrbetriq can also exacerbate symptoms in people with certain conditions such as uncontrolled high blood pressure (hypertension), urinary retention or gastric retention. Therefore, individuals with these conditions need to discuss their health status thoroughly with their doctor before starting treatment with either drug.

How much do Enablex and Myrbetriq cost?

For the brand name versions of these drugs:

The price for a pack of 30 tablets of Enablex (15 mg) averages around $400, which works out to roughly $13–26/day, depending on your dose.
The cost for a month's supply (30 tablets) of Myrbetriq (50 mg) is about $450, working out to approximately $15/day.

Thus, if you are in the higher dosage range for Enablex (i.e., 30 mg/day or more), then brand-name Myrbetriq may be less expensive on a per-day treatment basis. Please note that cost should not be a primary consideration in determining which of these drugs is right for you.

For generic versions of Enablex and Myrbetriq - darifenacin and mirabegron respectively - costs can differ significantly:

Darifenacin comes in packs ranging from 10 to 90 tablets with approximate costs varying between $1.40 and $5 per day depending on the quantity purchased and daily dosage required.
Mirabegron also comes in similar packaging options, with daily costs starting from as low as $.60/day up to about $2.80/day dependent upon the dosage taken and package size chosen.

Popularity of Enablex and Myrbetriq

Darifenacin, sold under the brand name Enablex among others, is used to treat overactive bladder. In 2020, it was estimated that about 800,000 prescriptions for darifenacin were filled in the US alone. The drug accounts for approximately 10% of all antimuscarinic prescriptions in America and its usage has been generally stable over the last decade.

Mirabegron, better known by its brand name Myrbetriq and also used for treating an overactive bladder condition, had a somewhat higher prescription rate in comparison with Enablex. Approximately 3 million people in the US were prescribed this medication during 2020. Mirabegron constitutes around 20% of beta-3 adrenergic agonist prescriptions across the country and just under 30% of overall medications intended to manage symptoms related with urinary disorders such as urgency or frequency. It's worth mentioning that mirabegron utilization has demonstrated a prevalent uptrend since its approval by FDA back in June 2012.

Conclusion

Both Enablex (darifenacin) and Myrbetriq (mirabegron) have significant records of usage in patients suffering from overactive bladder symptoms. They are supported by numerous clinical studies indicating that they can significantly reduce the frequency of urination, urgency, and episodes of urinary incontinence compared to placebo treatments. While both drugs may be prescribed together under certain circumstances, this should only occur under careful consideration by a physician due to potential drug interactions.

Their mechanisms of action differ: Enablex is an antimuscarinic agent which works primarily by relaxing the bladder muscles thereby reducing muscle spasms, whereas Myrbetriq is a beta-3 adrenergic agonist which increases bladder capacity by relaxing the detrusor muscle during urine storage phase.

Both medications are available as generic drugs representing cost benefits for those paying out-of-pocket; however, their prices still vary so it's best to consult with your healthcare provider or pharmacist regarding costs.

The side effect profile between these two medications differs somewhat but both are generally well-tolerated. Common side effects include constipation and dry mouth for Enablex while Myrbetriq might cause increased blood pressure along with headaches and common cold symptoms. For both drugs, patients must monitor their responses particularly when starting treatment and seek medical help immediately if severe adverse reactions develop such as difficulty breathing or swallowing.