Who cannot enter the trial
1. A history of significant disease deemed by the investigator to render the subject unsuitable for inclusion
2. Any significant ongoing painful condition other than that associated with primary dysmenorrhoea
3. Any ongoing condition that may interfere with the absorption, distribution, metabolism, or excretion of the study medication
4. A history of peptic ulcer, duodenal ulcer, gastrointestinal bleeding
5. A history of frequent dyspepsia, heartburn or indigestion
6. A history of psychotic illness, attempted suicide, or neurosis
7. A positive history of drug or alcohol abuse within the past year
8. Those taking any concomitant medications that might confound assessments of pain relief, such as psychotropic drugs, antidepressants, sedative?hypnotics taken within fives times of their elimination half lives. Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) are permitted if the subject has been on a stable dose for at least four weeks prior to Visit 1 (screening) and remain on this dose throughout the study.
9. Woman of childbearing potential, who are pregnant or lactating, seeking pregnancy or failing to take adequate contraceptive precautions, (i.e. an oral or injectable contraceptive, an approved hormonal implant or topical patch, an intrauterine device, abstinence [should the subject become sexually active, she must agree to use a double barrier method] or condoms/diaphragm and spermicide). A woman of childbearing potential is defined as any female who is less than 2 years post-menopausal or has not undergone a hysterectomy or surgical sterilisation, e.g. bilateral tubal ligation, bilateral ovariectomy (oophorectomy).
10. A history of inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis), a chronic or acute renal or hepatic disorder, a significant coagulation defect, or any previous history of allergy or known intolerance to any of the drugs or formulation constituents which, in the Investigator's opinion, might preclude use of an non-steroidal anti-inflammatory drug [NSAID], including aspirin sensitive asthma or a previous allergic respresponse to a NSAID, including bronchospasm, urticaria, angioedema and rhinitis)
11. Those previously randomised into this study
12. Subjects who have received any analgesic, anti-inflammatory, antispasmodic or other therapy for dysmenorrhoea within 6 hours of taking the study medication
13. Those who have participated in a clinical trial in the previous 30 days weeks are calculated from time of last dosing in the prior trial to time of anticipated dosing in this trial
14. Those suffering with anaemia ? (blood test at screening visit)
15. Those unable, in the opinion of the investigator, to comply fully with the study requirements