They are indirect catecholamine agonists and result in the release of newly synthesized norepinephrine and dopamine. In addition, amphetamines cause direct neuronal release of norepinephrine and blockade of catecholamine uptake.
Death directly resulting from acute overdose is extremely rare.
Tolerance to the anorectic effects of amphetamines can develop rapidly. The euphorogenic and other mood-altering effects of amphetamines appear to be subject to rapid development of tolerance. Tolerance to the psychosis-producing effects of amphetamines has not been reported. A chronic high dose of amphetamines results in physical dependence. Marked psychological dependence frequently results even among regular low dose users.