Ritalin (Methylphenidate) – A stimulant that produces effects similar to those of cocaine and amphetamines, is prescribed by doctors to treat attention deficit/hyperactivity disorder and other conditions. Illicitly used for effects of appetite suppression, wakefulness, increased attentiveness and euphoria. The drug can also produce increases in heart rate and blood pressure and is capable of producing severe psychological dependence.

Percocet and Percodan (Oxycodone) – A narcotic similar to codeine, it is more potent and has a higher dependence potential. Commonly prescribed by doctors for relief of severe pain.

Vicodin, Anexsia, Lorcet (Hydrocodone) – Sales and production of this narcotic have increased significantly, as has its illicit use. Available as tablets, capsules and syrups.

Dexadrine, Dexampex and Ferndex (Dextroamphetamine sulfate) – Attractive for its use as a stimulant and diet aid, it is prescribed to tread A.D.H.D. and narcolepsy. Withdrawal symptoms include stomach pain, trembling, severe depression, extreme weakness or tiredness and anxiety.

source: The New York Times