What is the recommended treatment for an older adult patient with overactive bladder, considering Gemtesa (vibegron) 75 mg?

Gemtesa (Vibegron) 75 mg for Overactive Bladder in Older Adults

Gemtesa (vibegron) 75 mg once daily is an appropriate and preferred pharmacologic option for older adults with overactive bladder, offering efficacy comparable to antimuscarinics with a superior safety profile, particularly regarding cardiovascular and cognitive risks. 1

Indications and Dosing

• Gemtesa is FDA-approved for treating overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency in adults 1
• The recommended dose is 75 mg orally once daily, taken with or without food 1
• Tablets should be swallowed whole with water, though they may be crushed and mixed with applesauce if needed 1

Treatment Algorithm for Older Adults

First, confirm true overactive bladder versus medication-induced frequency:

• Document void volumes using a bladder diary—small frequent voids suggest OAB, while larger volume voids suggest drug-induced polyuria (e.g., from diuretics or SGLT2 inhibitors) 2
• Check post-void residual in patients with emptying symptoms, neurologic disorders, or prior retention history 2

Second, initiate behavioral therapies for 8-12 weeks:

• Fluid management with strategic timing to reduce evening fluids while maintaining daytime hydration 3, 2
• Bladder training and urge suppression techniques should be offered to all patients 3, 2
• Behavioral therapies may be combined with pharmacologic management 3

Third, add vibegron as first-line pharmacologic therapy if behavioral measures are inadequate:

• Beta-3 agonists like vibegron are preferred over antimuscarinics due to lower cognitive risk and better tolerability 2
• This is particularly important in older adults where antimuscarinic cognitive effects are concerning 2

Efficacy in Older Adults

Vibegron demonstrates robust efficacy specifically in geriatric populations:

• In patients ≥65 years, vibegron significantly reduced daily micturitions (P<0.0001), urge incontinence episodes (P<0.001), and urgency episodes (P<0.01) versus placebo at 12 weeks 4
• In patients ≥75 years, similar significant improvements were observed: micturitions (P<0.05), urge incontinence (P<0.0001), and urgency (P<0.01) 4
• Onset of benefit begins as early as week 2 and is sustained through 52 weeks of treatment 5, 6, 4
• Among patients ≥65 years, 50.0% achieved ≥75% reduction in urge incontinence episodes versus 29.8% with placebo (P<0.0001) 4

Safety Profile in Older Adults

Vibegron has a favorable safety profile with minimal cardiovascular risk:

• Hypertension occurred in only 1.2% of patients ≥65 years receiving vibegron versus 3.1% receiving placebo 4
• In patients ≥75 years, hypertension occurred in 1.3% with vibegron versus 3.3% with placebo 4
• Cardiovascular adverse events occurred in <2% of older patients, similar to placebo rates 4
• Discontinuation due to adverse events was only 1.7% with vibegron versus 1.1% with placebo 6

Special Considerations for Frail Elderly

Exercise caution but do not automatically exclude vibegron in frail patients:

• The AUA/SUFU guidelines recommend caution when prescribing β3-adrenoceptor agonists in frail OAB patients (those with mobility deficits, weight loss, weakness, and cognitive deficits) 3, 7
• Frail patients may have a lower therapeutic index and higher adverse event profile with OAB medications 3, 7
• For patients who cannot tolerate pharmacologic management, behavioral strategies including prompted voiding and fluid management should be emphasized 3, 7

Monitoring Requirements

Regular monitoring ensures safe use:

• Monitor blood pressure, especially during initial treatment and in patients with pre-existing hypertension 7, 1
• Monitor for signs and symptoms of urinary retention, particularly in patients with bladder outlet obstruction or those taking concurrent antimuscarinic medications 1
• Discontinue vibegron if urinary retention develops 1

Critical Contraindications and Warnings

Absolute contraindication:

• Known hypersensitivity to vibegron or any component—angioedema has been reported and may be life-threatening 1

Urinary retention risk:

• Risk increases in patients with bladder outlet obstruction and those taking concurrent muscarinic antagonists 1
• Discontinue immediately if retention develops 1

Switching from Antimuscarinics

If a patient experiences inadequate symptom control or unacceptable adverse events with an antimuscarinic:

• Switching to a β3-adrenoceptor agonist like vibegron is appropriate given similar efficacy with a relatively lower adverse event profile 3
• Do not abandon pharmacologic therapy after one medication failure—trial of alternate agents is warranted 3
• Allow 4-8 weeks to assess efficacy of any new medication 3

Drug Interactions

Vibegron has minimal clinically significant drug interactions:

• No clinically significant interactions with CYP3A4 inhibitors (ketoconazole, diltiazem), CYP3A4 inducers (rifampin), or other common medications (tolterodine, metoprolol, warfarin, oral contraceptives) 1
• This favorable interaction profile is particularly beneficial for older patients with polypharmacy 8

Common Pitfalls to Avoid

• Do not use vibegron in patients with severe uncontrolled hypertension 7, 1
• Do not assume diuretic-induced frequency is OAB—use bladder diary to distinguish small-volume urgent voids from large-volume normal voids 2
• Do not check post-void residual routinely unless specific risk factors present (bladder outlet obstruction, neurologic disease, prior retention) 2, 1
• Do not combine with antimuscarinics initially—limited data exists on combination therapy and monotherapy should be optimized first 3