Much is known about the pharmacokinetics, pharmacodynamics, effects and toxicity of psychostimulants. Effects include euphoria, wellbeing, energy, wakefulness and alertness. Toxic effects include psychiatric, neurological, cardiovascular, cerebrovascular and metabolic presentations. Risks are a result of many factors and are not exclusively dose related. Several other drugs, including antidepressants, licit and illicit drugs, may alter psychostimulant effects and toxicity.