My friend has doubled his co-codomol usage. what are the dangers?

Dangerous: Doubling the dose of Codeine and tylenol (acetaminophen) are both dangerous codeine may cause problem with breathing tylenol (acetaminophen) component may damage the liver.

Addiction: The fact that he has (self?) increased his usage of this medication tells me he is becoming addicted to it, as the lower dose he was taking was no longer providing him with either pain relief, or the calm feeling of the "high" that the medication can cause. More concerning is the potential for a fatal overdose the more he takes. He probably needs professional help getting off the medication.