Constipation and weakening of bowel can be quite inconvenient side effects of opiate use.
Methamphetamine is also fairly safe (mainly psychosis and heart issues right?). Teeth falling out is more of a result of people tweaking for days without taking care of themselves. After all, methamphetamine is a Schedule II, prescribed, commercial medication.
Teeth falling out is more a consequence of smoking its hydrochloride. The vapor condenses to hydrochloric acid which has a predictable effect on teeth.
Amphetamines are not neurotoxic, methamphetamines are. If you want to read some scientific research search pubmed for methamphetamine neurotoxicity and you'll find a ton of results.
Methamphetamine is also fairly safe (mainly psychosis and heart issues right?). Teeth falling out is more of a result of people tweaking for days without taking care of themselves. After all, methamphetamine is a Schedule II, prescribed, commercial medication.