What Factors Go Into Finding Your Myrbetriq Dose?

What Factors Go Into Finding Your Myrbetriq Dose?

Myrbetriq (mirabegron) is a prescription medication used to treat an overactive bladder (OAB). As a non-OTC drug, it is given to patients with consideration to their specific conditions and other factors. Find out what they are below.

Myrbetriq Medication and Dosing

The recommended starting dose of Myrbetriq is 25 mg once a day with water (and with or without food). It may be increased to 50 mg throughout the initial eight weeks of treatment depending on the patient’s condition and level of toleration.

This medication takes two forms:

  • Myrbetriq –  which is an extended-release tablet
  • Myrbetriq granules  – which is an extended-release oral suspension and often prescribed to pediatric patients with a bladder dysfunction called neurogenic detrusor overactivity (NDO)

These two forms are completely different from each other and are not substitutable. With this said, it is safe to say that the form prescribed may depend on the patient’s age and specific diagnosis (e.g., able to excrete urine without a problem, able to metabolize medication, and the like).

Factors Affecting Myrbetriq Prescription Dosing

1. Weight and Age

For pediatric patients aged three years and older and weighing less than 77 lbs, Myrbetriq granules are prescribed. Here is a summary of dosing per body weight:

  • 24 lbs to less than 48.5 lbs – Min: 3 ml (24 mg) to Max: 6 ml (48 mg) once a daily
  • 48.5 lbs to 77 lbs – Min: 4 ml (32 mg) to Max: 8 ml (64 mg) once daily

Pediatric patients weighing 77 lbs or more may use the oral suspension form or the oral tablet. Dosing is as follows:

  • Oral tablet – 25 mg to 50 mg once a day for 4-8 weeks
  • Granules for oral suspension – 6 ml (48 mg) once a day for 4 to 8 weeks and may be increased to 10 ml (80 mg) after

2. Kidney and Liver Condition

The standard starting dose of 25 mg once a day is strictly followed for patients with severe renal impairment and moderate hepatic impairment.

Here are the specific once-a-day dosages per estimated glomerular filtration rate (GFR) or the numerical determinant of the kidneys’ function:

  • GFR of 30-89 ml/min/1.73 m2 – 25 mg to 50 mg once a day
  • GFR 15-29 ml/min/1.73 m2 -25 mg once daily

As for liver impairment dosing, follow this standard:

  • Mild hepatic impairment – 25 mg to 50 mg once a day
  • Moderate hepatic impairment – 25 mg once per day

Note: Patients with end stage renal disease (and undergoing dialysis) and/or severe hepatic impairment are prohibited from taking Myrbetriq.

3. Special Combination Conditions

Myrbetriq Oral Suspension

Myrbetriq granules for oral suspension are prescribed to pediatric patients aged 3 years or older with kidney or liver impairment and weighing less than 77 lbs.

Here are the specific once-a-day doses based on level of liver impairment:

  • Mild hepatic impairment and weighing 24 lbs to less than 48.5 lbs – 3 ml (24 mg) to 6 m (48 mg)
  • Mild hepatic impairment and weighing 48.5 lbs to 77 lbs – 4 ml (32 mg) to 8 ml (64 mg)
  • Moderate hepatic impairment and weighing 24 lbs to less than 48.5 lbs – 3 ml (24 mg)
  • Moderate hepatic impairment and weighing 48.5 lbs to 77 lbs – 4 ml (32 mg)

As for the specific once-a-day dosages per estimated glomerular filtration rate (GFR) of the kidneys:

  • GFR 30-89 ml/min/1.73 m2  and weighing 24 lbs to less than 48.5 lbs – Min: 3 ml (24 mg) to Max: 6 ml (48 mg)
  • GFR 30-89 ml/min/1.73 m2  and weighing 48.5 lbs to 77 lbs – Min: 4 ml (32 mg) to Max: 8 ml (64 mg)
  • GFR 15-29 ml/min/1.73 m2 and weighing 24 lbs to less than 48.5 lbs – 3 ml (24 mg)
  • GFR 15-29 ml/min/1.73 m2 and weighing 48.5 lbs to 77 lbs – 4 ml (32 mg)

Note: A GFR of less than 15 ml/min/1.73 m2 and undergoing dialysis or a level classification of severe hepatic impairment restricts a patient from taking Myrbetriq granules.

Myrbetriq Tablet

Pediatric patients weighing 77 lbs or more and are diagnosed with renal or hepatic impairment may be  prescribed with the tablet or granule form.

Here are the starting and maximum dosages per estimated GFR:

  • GFR 30-89 ml/min/1.73 m2 – 6 ml (48 mg) to 10 ml (80 mg)
  • GFR 15-29 ml/min/1.73 m2 – The standard dose is 6 ml (48 mg).

Note: Again, a GFR of less than 15 m/min/1.73 m2 and the use of dialysis prevent one from taking a Myrbetriq prescription.

Hepatic impairment and a weight of 77 lbs or more in pediatric patients follow this standard dosing:

  • Mild hepatic impairment – 6 ml (48 mg) to 10 ml (80 mg)
  • Moderate hepatic impairment – 6 ml (48 mg)
  • Severe hepatic impairment- Myrbetriq is not recommended.

Myrbetriq Is Not for Everyone

As presented above, not all patients with a bladder condition can take Myrbetriq. Factors such as age, weight, and liver and kidney disease come into play when determining the eligibility for the drug and its dose. It is also important to note that Myrbetriq is not given to patients with high blood pressure and bladder obstruction.

If you are someone who is already on the medication, watch out for side effects like headache, increased heart rate, nausea, dizziness, localized allergic reactions, pain when or difficulty urinating, and constipation. Stop taking the drug and call your doctor or seek immediate medical assistance should you experience any of these. 

And while Myrbetriq has proven  very effective in overactive bladder management, we must always remember that it should only be taken with a proper prescription from a health care professional. That said, if your body has been responding well to the effects of Myrbetriq on urinary control, make sure you comply with your prescription and don’t run out of supply. 

Get your prescription filled today at PharmaServe. We have Myrbetriq coupons you can use for discounted purchases, and our experienced team is happy to assist you in your medication needs.

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