Effect of Celecoxib and Etoricoxib on the Pharmacokinetics and Pharmacodynamics of Oral Tramadol

Inclusion Criteria: * Healthy volunteers * Age 18-40 * Body weight within ±15% of the ideal weight for height Exclusion Criteria: * A previous history of intolerance to the study drugs or to related compounds and additives * Concomitant drug therapy of any kind for at least 14 days prior to the study * Existing or recent significant disease * History of hematological, endocrine, metabolic or gastrointestinal disease, including gut motility disorders * History of asthma or any kind of drug allergy * Previous or present alcoholism, drug abuse, psychological or other emotional problems that are likely to invalidate informed consent, or limit the ability of the subject to comply with the protocol requirements * A positive test result for urine toxicology * A "yes" answer to any one of the Abuse Questions * Pregnancy or nursing * Donation of blood for 4 weeks prior and during the study * Special diet or life style conditions which would compromise the conditions of the study or interpretation of the results * Participation in any other studies involving investigational or marketed drug products concomitantly or within one month prior to the entry into this study * Smoking for one month before the start of the study and during the whole study period * Any history of coagulation abnormality, also in first degree relatives