A Study of the Pharmacokinetics and Pharmacodynamics of MK4618 in Women With Overactive Bladder (MK-4618-004 AM1)

Participants will be randomized in each of 2 treatment periods to 1 of 4 possible
treatments, which will be administered in double-dummy fashion, and participants will
undergo urodynamic procedures prior to dosing on Day 1 and after 7 days of treatment.

Inclusion Criteria:

- Non-child bearing potential (status post menopausal or post hysterectomy,oophorectomy
or tubal ligation). If of reproductive potential, must be non-pregnant (confirmed via
blood test) and agree to use (and/or have their partner use) two acceptable methods
of birth control beginning at least 2 weeks prior to administration of the first dose
of study drug,throughout the study (including washout intervals between treatment
periods/panels) and until at least 2 weeks after administration of the last dose of
study drug in the last treatment period.

- Body mass index (BMI) of ≤40 kg/m^2 (ie, not morbidly obese)

- Clinical history of overactive bladder symptoms (OAB) for at least 3 months

- Capable of completing an accurate daily diary for reporting purposes

Exclusion Criteria:

- Mentally or legally incapacitated, such as significant emotional problems (other than
situational depression) or diagnosed with a significant psychiatric disorder during
the past 5-10 years

- Other types of urinary incontinence (ie,stress or mixed)

- History (current or past)of interstitial cystitis, painful bladder syndrome, or
chronic pelvic pain or Stage III or greater pelvic organ prolapse

- Other types of kidney/urinary bladder disease/obstruction or infection. Participants
with with a history of uncomplicated kidney stones may be enrolled in the study at
the discretion of the investigator

- Inability to control bowel movements

- History of narrow angle glaucoma, immunocompromise, stroke, chronic seizures, major
neurological disorders and/or other serious and chronic organ-system health
conditions (ie, heart disease)

- Urinary catheter, either permanent or intermittent placement

- Failure to meet medication profile requirements or directives required for study
eligibility

- Condition for which there is a warning, contraindication, or precaution against the
use of tolterodine ER or anticipates the use of prescription medications
contraindicated with the use of tolterodine ER

- Daily alcohol or caffeine intake exceeds study requirements (for alcohol: defined as
greater than 2 glasses of alcoholic beverages (1 glass is approximately equivalent
to: beer [284 mL/10 ounces], wine [125 mL/4 ounces], or distilled spirits [25 mL/1
ounce]) per day; and for caffeine: defined as greater than 3 servings (1 serving is
approximately equivalent to 120 mg of caffeine) of coffee,tea, cola, or other
caffeinated beverages (ie, Red Bull) per day

- Inability to refrain from smoking throughout the study's duration

- Illicit drug use

- Recent surgery or recent participation in another clinical trial

- Severe, frequent allergies or history of life-threatening reactions or intolerability
to prescription or non prescription medications or food

- Intended or unintended extended absence or exposure to significant change in time
zone or sleep schedule (ie, transmeridian travel or shift work) that will interfere
with accurate completion of scheduled daily diary entries