A study published in the British Medical Journal says the drug Tamiflu doesn't do much to relieve flu symptoms and could put patients at risk for other serious health problems. Researchers say it does not prevent the spread of the disease and only relieves symptoms by about half a day for adults and hardly at all for children. They called its effects no better than acetaminophen. The study also found Tamiflu does little to prevent hospitalization and pneumonia and linked it to an increased risk of kidney problems, nausea, headaches and depression. Barry Clinch, a spokesman for Roche Pharmaceutical, the manufacturer of Tamiflu, said researchers took the wrong data from the company's clinical trials and made mistakes when drawing their conclusions.