Mirago (Mirabegron 50mg) Tablets

Mirago general information

What is Mirago used for?

Loss of bladder control or urinary incontinence can severely affect your quality of life.  You may feel restricted in your activities and anxious to stay close to a bathroom.  This common condition is known as overactive bladder, which means that the bladder contracts suddenly and without your control, and can happen at any time.  With an overactive bladder, you feel the need to urinate more often, which increases the frequency of urination as well as giving you a sense of urgency to urinate.  You will also experience frequent urination at night.  Mirago tablets 50mg are used to treat overactive bladder to relieve symptoms and improve quality of life.

Overactive bladder

The muscle of the bladder wall is called the detrusor muscle, and it is made up of fibers of smooth muscle that stretch as the bladder fills with urine.  Usually, the detrusor muscle is relaxed as the bladder fills with urine.  The filling and emptying of the bladder are regulated by the autonomic nervous system, which is the component of the central nervous system that supplies nerves to smooth muscle, glands and organs.  The autonomic nervous system controls body functions that happen without us being aware of them.  There are two components of the autonomic nervous system.  The parasympathetic nervous system controls the relaxation of the bladder as it fills.  The sympathetic nervous system controls bladder contraction when the bladder empties. 

Under normal conditions, we can control the urge to empty the bladder as it fills, and the detrusor muscle stretches.  When the bladder is full, nerve fibers are triggered, and a nerve signal is sent to stimulate contraction of the detrusor muscle, which empties the bladder contents.  Normally, when we empty the bladder is under our control.  However, anything that interferes with or damages transmission of the nerve signal to the detrusor muscle can cause bladder spasms, which is when the muscle contracts uncontrollably.  Detrusor muscle spasm causes the bladder to become overactive, disrupting normal bladder function.  This can result in the urge for you to pass urine frequently, and can also lead to urinary incontinence. 

Often there is no identifiable reason for overactive bladder, which is also known as irritable bladder or detrusor instability.  However, some neurological disorders can cause loss of bladder control, such as Parkinson’s Disease and Multiple Sclerosis.  Other neurological causes include damage to the brain or spinal cord after an injury and destruction of the nerves due to diabetes (diabetic neuropathy).  Also, overactive bladder can develop following a urinary infection. 

Symptoms

Overactive bladder symptoms include urgency to urinate, which cannot wait or that you cannot control as you would normally be able to with a full bladder.  Frequent urination is a symptom due to the sensation of an increased need to urinate.  You may be woken regularly in the night by the urgent need to urinate.  This condition is also called urge incontinence.  It is not the same condition as other forms of incontinence, such as stress incontinence, when an action like a sneeze, cough or heavy lifting causes urine leaks, or overflow incontinence, when you are unable to fully empty your bladder or don’t feel the urge even when your bladder is full.  These types of incontinence have different causes and result in uncontrolled urine leaks even if you have recently emptied your bladder.  Urge incontinence means you get strong and sudden urges to pass urine even when your bladder isn’t full and can lead to leaks if you don’t manage to get to the bathroom in time. 

How does Mirago work?

Mirago tablets 50mg contain mirabegron, a potent and selective beta 3-adrenoceptor agonist that is used to treat overactive bladder and relieve symptoms. 

The storage of urine in the bladder and the emptying of urine from the bladder are two separate processes.  These processes are controlled by different nerve pathways between the brain and the nerves that supply the pelvic floor muscles (surrounding the base of the bladder) and the bladder wall. 

As the bladder fills with urine, the detrusor muscle stretches, and the sympathetic nervous system is activated.  Nerve endings release the neurotransmitter norepinephrine (noradrenaline), a chemical messenger that allows nerve cells to communicate.  Norepinephrine binds to beta 3-adrenergic receptors on the bladder and stimulates relaxation of the bladder detrusor muscle, which prevents the bladder from suddenly contracting without your control.

When the bladder is full and needs to be emptied, the parasympathetic nervous system is activated.  The chemical messenger acetylcholine is released, and this binds to receptors called cholinergic (or muscarinic) receptors.  Stimulation of the cholinergic receptors by acetylcholine causes contraction of the detrusor muscle so that the bladder can empty normally. 

Stimulation of the beta 3-adrenoceptors by mirabegron prevents the spontaneous and involuntary contractions of the bladder wall as the bladder is filling.  This action of mirabegron in Mirago tablets 50mg controls symptoms of overactive bladder, without interfering with normal emptying of the bladder.  Also, the bladder can store more urine without a sense of urgency to empty the bladder when it is not full.  This reduces the risk of incontinence.

Mirago tablets 50mg are particularly helpful for those who cannot tolerate medications based on blocking the cholinergic/ muscarinic receptors, known as anticholinergics/antimuscarinics.  Mirago tablets 50mg usually has fewer side effects than anticholinergic drugs.  Therefore, this results in better compliance with taking the medication.

What does Mirago contain?

Mirago tablets 50mg contain the active ingredient mirabegron, a beta 3-adrenoceptor agonist that is used to treat overactive bladder and relieve symptoms. 

What are the side effects of Mirago?

Most medications have some side effects, but they are not experienced by everyone.  Some side effects are commonly experienced when taking Mirago tablets 50mg, but others are not so common, and you should discuss any problems or concerns with your primary care physician. 

Common side effects when taking Mirago include headache, dizziness, nausea, constipation, diarrhoea, urinary tract infection, rapid heartbeat (tachycardia).

When should Mirago not be used?

Have a talk with your primary healthcare physician before taking Mirago tablets 50mg so that you have a full understanding of what this medicine is for and how to use it.  There are some reasons for not taking a medication; these are called contraindications, and for Mirago you should consider the following before taking Mirago:

• Have you ever had an unusual reaction or an allergy when taking Mirago?
• Are you pregnant or breastfeeding?
• Do you have any problems with your kidneys or your liver?
• Do you have severe uncontrolled hypertension (high blood pressure)?
• Have you had any problems with urine flow or bladder obstruction, or trouble emptying your bladder?

What medications interact with Mirago?

Some medicines interact with Mirago tablets 50mg and may affect the way it works, or are affected by Mirago or increase side effects; you should discuss possible interactions with your primary care physician.  These may include digoxin for heart failure, the antiarrhythmic flecainide, the antidepressant imipramine, the antipsychotic thioridazine, the anticoagulant dabigatran. 

If other medications may interact with Mirago, your doctor will discuss these with you. 

How should Mirago be taken and for how long?

You should take your Mirago tablets 50mg swallowed whole, with or without food and once daily.  The dose you take and for how long depends on how you respond, any side effects and your doctor’s recommendation.  You should continue to take your Mirago tablets 50mg for as long as recommended by your doctor, which will usually be at least eight weeks.

Missed dose of Mirago

If you miss a dose of Mirago tablets 50mg take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Mirago be stored?

You should store your Mirago tablets 50mg below 25°C in a cool dry place.