Can Mirabegron (Myrbetriq) tablets be split?

Mirabegron Tablets Should Not Be Split

Mirabegron (Myrbetriq) extended-release tablets should not be split, crushed, or chewed as this would compromise the extended-release mechanism and potentially affect drug efficacy and safety. 1

Why Mirabegron Tablets Cannot Be Split

Mirabegron is formulated as an extended-release tablet using oral controlled-absorption system (OCAS) technology 2. The FDA-approved drug label specifically instructs:

• Adults should "swallow mirabegron whole with water and not to chew, divide, or crush" 1
• Similarly, pediatric patients and/or their caregivers are instructed "to swallow mirabegron extended-release tablets whole with water and not to chew, divide, or crush" 1

These instructions are not merely suggestions but critical to maintaining the medication's intended release profile. Splitting the tablet would:

1. Disrupt the extended-release mechanism
2. Potentially lead to dose dumping (rapid release of the entire dose)
3. Change the pharmacokinetic profile of the medication
4. Potentially increase the risk of adverse effects

Administration Recommendations

For patients who cannot swallow mirabegron tablets whole:

• Adults can take mirabegron extended-release tablets with or without food 1
• Children should take mirabegron extended-release tablets with food 1
• For pediatric patients weighing less than 35 kg, an extended-release oral suspension formulation (Myrbetriq Granules) is available 3
• The tablet and oral suspension formulations are not substitutable on a mg-by-mg basis 3

Potential Risks of Splitting Extended-Release Tablets

While a systematic review of tablet splitting found that many concerns about splitting conventional tablets are not supported by evidence, it specifically noted that "sustained-release tablets should not be split, given the potential for alteration of the rate of drug release" 4. This applies to mirabegron's extended-release formulation.

Splitting extended-release tablets like mirabegron could lead to:

• Unpredictable drug release patterns
• Potential toxicity from rapid absorption
• Reduced efficacy due to altered pharmacokinetics
• Increased risk of adverse effects such as increased blood pressure, urinary retention, or angioedema 1

Clinical Implications

Mirabegron's pharmacokinetics are already affected by food intake, with a greater reduction in exposure observed after a low-fat breakfast compared to a high-fat breakfast 2. Adding the variable of a split tablet would further complicate the drug's absorption profile and potentially affect clinical outcomes.

For patients who need dose adjustments or have difficulty swallowing tablets, clinicians should consider:

1. Using the appropriate strength tablet (available in 25 mg and 50 mg strengths)
2. Using the oral suspension formulation for pediatric patients
3. Consulting with a pharmacist about alternative formulations or medications if necessary

Conclusion

Based on the FDA-approved labeling and the extended-release nature of mirabegron tablets, splitting these tablets is not recommended and could compromise both safety and efficacy.