Phentermine and
methamphetamine (meth) are both chemically related to the drug
amphetamine, so though the two drugs have similar properties, they are different.
Both drugs are stimulants (as are all amphetamines), but the stimulant effects of methamphetamine are greater, making methamphetamine very addictive with a high potential for abuse and dependence.
Amphetamines along with stimulant properties, also have appetite suppressing properties. The stimulant effects of phentermine increase your heart rate and blood pressure and decrease your appetite. The appetite suppressing effect of phentermine tends to decrease after a few weeks and therefore this drug is only useful during the first few weeks of a weight-loss program.
You will find info at
http://phentermine.drugs.com