Taking little too much Paracetamol, the pain and fever reducer whose best known brand name is Tylenol, can cause a dangerous overdose that is difficult to recognize and has potential to cause death.

Many people commonly take Tylenol (Paracetamol), a widely available over the counter medication for pain, muscle cramps, and headaches.

However staggered overdoses - if not recognized and treated - immediately put patients at risk of dangers greater than single overdose.

Staggered overdoses occur when people repeatedly take a little more Paracetamol than they should for pain.

"They haven't taken the sort of single-moment, one-off massive overdose taken by people who try to commit suicide, but over time the damage build up, and the effect can be fatal," said Dr. Kenneth Simpson, author of the research published in the British Journal of Clinical Pharmacology.

Dr. Simpson and his team with the University of Edinburgh and the Scottish Liver Transplantation Unit analyzed data from around 660 patients who have been admitted with Paracetamol-induced liver injury and found 161 of the cases were due to staggered overdose.

"On admission, these staggered overdose patients were more likely to have liver and brain problems, require kidney dialysis or help with breathing and were at a greater risk of dying than people who had taken single overdoses," said Simpson. The problem is also worse for people who arrive at the hospital more than a day after taking an overdose - they are also at high risk of dying or needing a liver transplant.

Researchers believe that doctors urgently need to find new ways of assessing whether a patient can be sent home, need medical treatment to counteract the Paracetamol or need to be considered for a liver transplant.