BOSTON -- It's a drug celebrated by teenagers for causing dangerous psychedelic effects, yet it's being sold over the counter in grocery stores and pharmacies everywhere. It causes paranoia, excitability, brain damage, memory loss and psychological addictions, and is responsible for a growing number of teen overdoses in the United States. The drug is called dextromethorphan (DXM), and teenagers have no problem finding it.

Approved by the Food and Drug Administration in 1958 for the suppression of coughs, DXM is an over-the-counter drug found in more than 80 varieties of cough syrups in brands such as, Robitussin, Vicks Formula 44, and Drixoral Cough liquid caps. Not all medicines under these brands, however, contain the drug since most brands put out several formulations. The drug is found in a variety of forms, including gel caps, capsules and syrup and can be extracted from liquid cough syrup. It can be then taken orally, injected or snorted, according to the United States Department of Health and Human Services

DXM is in a class of drugs recognized as dissociative anesthetics, known for immobility and disassociation from self. It has side effects comparable to street drugs PCP and ketamine. It is commonly abused by teens for its hallucinatory properties and it's ability to prolong and enhance the effects of other drugs, according to the National Institute on Drug Abuse.

Exact numbers for overdoses and DXM use are difficult to determine since the drug is available over the counter and its main users are teens under 18, but the Massachusetts Department of Public Health reports a 4 percent increase in over-the-counter drug use since January 2002.

The drug is safe for treating coughs at the recommended dose of 15 mg to 30 mg, but the effects of the drug vary with dosage.

DMX users describe a set of distinct "plateaus" -- ranging from a mild stimulant effect with distorted visual perceptions coming from lose doses to a sense of complete dissociation from one's body at doses of 10 ounces or more. DMX trips usually last for six hours, health officials said.

Adding to the danger is that over-the-counter medications that contain dextromethorphan often contain antihistamine and decongestant ingredients as well, which mixed in high doses can have fatal results.

Side effects associated with higher levels of DXM include, spontaneous memory recall, complex delusions, hallucinations, out of body experiences, and perceived contact with spiritual or alien entities, officials said.

DMX is particularly dangerous for people taking any type of antidepressant, especially those taking monoamine oxidase inhibitors, diet drugs like phentermne, fenfluramine, or phen-fen, and nondrowsy antihistamines and allergy medications, such as Allegra, Seldane, and Hisminal.