Health - Amphetamines and the liver

[Dexyfiend]

Hey all,
was just wondering if anyone knew anything about liver damage due to amphet use/abuse. SWIM uses a rather high dose of amphets every weekend at most and bi-monthly at least.
He went to hospital the other day for a mild case of aceteminophen poisoning and would like to know how much harm he's doing to himself by doing amphets (he's not going to stop but would like to know how much damage if any he's doing to himself).
He'd ask his doctor but does not trust thier advice when it comes to illicit drug information.

Thanks SWIY's