How do these medications work?
Anticholinergics inhibit the binding of acetylcholine to the muscarinic receptors in the detrusor, thereby suppressing involuntary bladder contractions. This results in an increase in bladder volume voided and a decrease in micturition frequency, the sensation of urgency, and the number of urge incontinence episodes. An extended-release form, which you take once a day, might cause fewer side effects than the immediate-release versions, which are usually taken multiple times a day.
These medications are usually given as a pill or tablet that you take by mouth. Numerous formulations are available ranging from immediate release to extended release and in different strengths of medication.
It can take several weeks before your symptoms begin to improve on this type of medication. It might take 12 weeks to have the full effect.
For detailed information regarding the safety and efficacy of individual medications click the link below.
Beta-3 Adrenergic Agonists
The drug mirabegron (Myrbetriq) is the first in a class of drugs called beta-3 adrenergic agonists. These medications work by activating a protein receptor in bladder muscles that relaxes them and helps the bladder fill and store urine.
Compared to other OAB drugs, this medication stimulates bladder relaxation and should have fewer side effects.
AUA Guidelines for OAB
These are the American Urologic Association (AUA) guidelines for OAB medical treatment:
- If an immediate release (IR) and an extended-release (ER) formulation are available, then ER formulations should preferentially be prescribed over IR formulations because of lower rates of dry mouth.
- If a patient experiences inadequate symptom control and/or unacceptable adverse drug events with one antimuscarinic medication, then a dose modification or a different antimuscarinic medication or a β3-adrenoceptor agonist may be tried.
- Clinicians should not use antimuscarinics in patients with narrow-angle glaucoma unless approved by the treating ophthalmologist and should use antimuscarinics with extreme caution in patients with impaired gastric emptying or a history of urinary retention.
- Clinicians should manage constipation and dry mouth before abandoning effective antimuscarinic therapy. Management may include bowel management, fluid management, dose modification or alternative antimuscarinics.
- Clinicians must use caution in prescribing antimuscarinics in patients who are using other medications with anticholinergic properties.
- Clinicians should use caution in prescribing antimuscarinics or β3-adrenoceptor agonists in the frail OAB patient.