BACKGROUND: Orally administrated nonsteroidal anti-inflammatory drugs are effective in the treatment of a variety of acute and chronic pain conditions but their use may be associated with serious systemic adverse effects which are correlated with the therapeutic plasma levels of the drug. In order to minimize the incidence of drug related systemic events, topical formulations of the nonsteroidal anti-inflammatory drugs have been developed. A recently performed review of the evidence from randomized, double-blind, placebo controlled trials with topically applied NSAIDs in the treatment of acute pain confirmed the previously described pain relief effectiveness. For all topical nonsteroidal anti-inflammatory drugs combined, in comparison to placebo, the number needed to treat (NNT) to achieve a clinically meaningful pain relief of 50 % was 4.5 (3.9 to 5.3) for treatment periods of 6 to 14 days. Local skin reactions were generally mild and transient, and did not differ from placebo. OBJECTIVES: The present is an observational, multicenter, open-label, non-interventional, post-authorization safety study as it is defined by Article 21 of the European Clinical Trials Directive 2001/20/EC. The main objective of this study was to evaluate the local tolerability and the therapeutic efficacy of static and pain on movement intensity reduction of Ketospray® 10% cutaneous spray solution administered in accordance with the terms of the marketing authorization and last version of summary of product characteristics approved by National Medicines Agency of Romania. METHODS: In compliance with the Post-marketing study type, the assignment of the patient to a particular therapeutic strategy fell within current practice. The prescription of the medicine was not subject to compliance with predefined patients' characteristics. No specific, out of the daily practice routine diagnostic, monitoring, instrumental or laboratory assessments were foreseen by the study protocol. Patients' data were collected into respective case report forms. Study medication, Ketoprofen 10% Cutaneous Spray Solution was administered to the affected area at the dose of 3-6 spray puffs, 2-3 times a day, for 7 days. According to the study type, descriptive statistical methods were applied. Since almost half of the patients were treated with combination of the pain relieving medications, sizing of the pain relieving effects, as NNT, between the two groups was made. FINDINGS: There were 2020 study subjects in safety and ITT analysis population and 1802 (89%) in PP efficacy analysis population. There were 4 types of injuries: non-complicated strain-sprain (555), soft tissue contusion (323), low back pain (461) and osteoarthritis (681 patients). Ten patients reported 13 side effects of which 10 were recognized by investigators as adverse drug reactions. All side effects were non-serious, listed, application site skin changes. Remarkable reductions of static and pain on movement intensity were experienced by patients irrespective of the type of the injury and the type of the treatment. However, a clinically meaningful benefit of the concomitantly prescribed pain relieving medications was not observed for any type of pain. The lowest NNT (14) was obtained for the reduction of pain at rest in patients with strain-sprain or soft tissue contusions. The highest NNT (283) was for pain at rest in patients treated for the exacerbation of the chronic pain. CONCLUSIONS: The results of the current post-authorization study confirm beneficial pain intensity reducing efficacy of Ketospray 10% associated with good local tolerability of 7 days treatment course. Concomitant administration of systemic pain relieving medication did not substantially contribute neither to the relief of pain at rest nor of pain on movement among the subjects of respective study populations.