An antidepressant prescribed in the UK over the last 13 years is ineffective and potentially harmful, according to a damning study published today.

The drug, reboxetine, which is known in the UK under the trade name Edronax, works no better than a placebo, or dummy pill, say scientists in the British Medical Journal, who accuse the manufacturer, Pfizer, of failing to disclose the results of trials which show its inadequacies.

The licensing authorities and Nice, the National Institute for Health and Clinical Excellence, will now be forced to look again at the drug. Nice said in guidance on treating adults with depression that reboxetine works as well as other modern antidepressants. The BMJ authors say it does not.

The revelations come from the German Institute for Quality and Efficiency in Health Care. Its independent scientists decided to scrutinise the data on reboxetine because of doubts that have been raised about its effectiveness and the fact that the US licensing authority, the Food and Drugs Administration (FDA) refused it a licence in 2001.

Individual trials that have been published and reviews of the data in the public domain have all shown the drug to be effective. But the German institute's scientists found that eight out of 13 significant trials had not seen the light of day.

The manufacturer, Pfizer, gave them data relating only to 1,600 patients – although sources suggested the drug had been trialled on 4,600. Pfizer stated publicly it had given the institute "those data that from our point of view are suited for a benefit assessment of Edronax", but eventually handed over most of the rest.

The institute accuses the manufacturers of publishing only positive results for the drug. "Data on 74% of the patients included in our analysis was unpublished, indicating that the published evidence on reboxetine so far has been severely affected by publication bias," the authors write.

"Our comparison of published and unpublished trials confirmed this assumption: the positive benefit-risk ratio of reboxetine in the published literature was changed to a negative ratio if unpublished trials were added to the analysis."

Beate Wieseler, deputy head of the institute's department of drug assessment, and colleagues call for changes in European law to make it mandatory for all clinical trial results to be published. They argue that all trial data should be disclosed – even when the trials fail and the drug is not approved. The results should also be disclosed for all older drugs which have a licence and may not be covered by new rules.

In a commentary, Robert Steinbrook from Dartmouth and Yale and Jerome Kassirer from Tufts University schools of medicine in the US point to recent controversies involving the non-disclosure of data from drug trials. Avandia for diabetes and the painkiller Vioxx were both found to have safety problems that published studies had not shown up.

"Companies have financial interests in the outcome of the studies they sponsor; they own the data, and set the rules for access to the data. Unfortunately, they cannot be relied on to consistently provide dispassionate evaluations of their own drugs and medical devices," they say. Scientists and doctors may also have financial links to the companies.

Dr Fiona Godlee, editor of the BMJ, and colleague Dr Elizabeth Loder say that "the medical evidence base is distorted by missing clinical trial data" and call for urgent action to restore trust in existing evidence.

"Full information about previously conducted clinical trials involving drugs, devices and other treatments is vital to clinical decision-making," they say. "It is time to demonstrate a shared commitment to set the record straight."