Study to Assess the Safety and Efficacy of Etoricoxib Versus Ibuprofen in the Treatment of Dysmenorrhea (MK-0663-145 AM1)

This is a study to determine the overall analgesic effect of a single oral dose of etoricoxib compared to ibuprofen in participants with moderate-to-severe primary dysmenorrhea.

Participants who meet all the study entry criteria will be randomly allocated to 2 possible sequences of the 2 treatment regimens over the course of 2 menstrual cycles.

In treatment sequence 1, participants will receive etoricoxib 120 mg daily in menstrual cycle 1, and ibuprofen up to 2400 mg/daily in menstrual cycle 2. In treatment sequence 2, participants will receive ibuprofen up to 2400 mg/daily in menstrual cycle 1 and etoricoxib 120 mg daily in menstrual cycle 2.

Eligibility Criteria:
Inclusion Criteria:

* Agree to remain abstinent or use double-barrier contraception throughout the study. Participants who are status post tubal ligation are exempt from this requirement.
* Moderate or severe primary dysmenorrhea during a minimum of 4 of the previous 6 menstrual cycles. Moderate: Over-the-counter analgesics provide significant relief in most menstrual cycles; discomfort interferes with usual activity. Severe: Over-the-counter analgesics not consistently effective, or prescription analgesics required in at least some menstrual cycles; discomfort is incapacitating causing an inability to work or do usual activity.
* Willing to limit alcohol intake to 2 drinks or equivalent per day for the duration of the study and follow-up period as well as to avoid exercise during the first 24 hours postdose in each menstrual cycle.
* Able to read, understand, and complete diary.

Exclusion Criteria:

* Use of an intrauterine device. Pregnant, breast feeding, or \<6 weeks postpartum.
* Active gastric ulcer or history of inflammatory bowel disease.
* Uncontrolled hypertension.
* Uncontrolled diabetes mellitus or renal disease.
* Class II-IV congestive heart failure.
* Coronary artery bypass graft surgery, angioplasty, myocardial infarction, cerebrovascular accident or transient ischemic attack within the past 6 months.
* Unstable angina.
* Mild, moderate, or severe hepatic insufficiency.
* Any personal or family history of an inherited or acquired bleeding disorder.
* History of neoplastic disease; Exceptions: 1)adequately treated basal cell carcinoma or carcinoma in situ of the cervix; 2) other malignancies which have been successfully treated \> or equal to 5 years prior to screening. Participants with a history of leukemia, lymphoma, malignant melanoma, and myeloproliferative disease are ineligible for the study regardless of the time since treatment.
* Allergic to etoricoxib, ibuprofen, acetaminophen, indomethacin, or other nonsteroidal anti-inflammatory drugs (NSAIDs), or cyclooxygenase (COX)-2 inhibitors, or to components in Saridon (propyphenazone/paracetamol/caffeine).
* Recent history of chronic analgesic or tranquilizer use or dependence.
* Morbidly obese and demonstrates significant health problems stemming from the obesity.
* Current user of recreational or illicit drugs or had a recent history of drug or alcohol abuse or dependence.
* Participated in another clinical study within the last 4 weeks.
* Not able to swallow oral medications: surgical or anatomical conditions that will preclude from swallowing and absorbing oral medications on an ongoing basis.