The Maryland legislature, reacting to statewide concern over teenagers' increasing abuse of the synthetic drug PCP, enacted legislation yesterday to double the maximum prison term for those convicted of its sale or manufacture.

PCP is beginning to rival marijuana as the drug of choice of teen-agers in both Montgomery and Prince George's counties, officials claim, and it is reportedly being produced in large quantities in clandestine chemical labs throughout the Washington area.

"Right now this is one of the most serious drugs in the state of Maryland." Timothy E. Clarke, a deputy state's attorney from Montgomery County, testified before the legislature recently. "Kids seem to think it's the thing to take this drug . . . and the effects can be four to eight hours of extensive motor and physical damage to the body."

The bill, passed by the Senate yesterday after clearing the House earlier this session, is expected to be signed by Acting Gov. Blair Lee III. It would make anyone who is convicted of making or distributing PCP subject to a maximum prison term of 10 years and raise the maximum fine from $15,000 to $20,000.

One of the reasons for the increase in the drug's use in the community is the ease with which it can be manufactured, according to Richard L. Hamilton, director of Maryland's drug abuse administration.

All that is needed, according to Hamilton, are ordinary chemicals "you can pick up at any drug supply house." He said they can easily be mixed to produce PCP, the popular abbreviation for the drug phencyclidine, "in your kitchen."

Another reason for its popularity is that it comes in a variety of forms, according to researchers who have studied the drug and its abusers.

"Angel dust," as it is sometimes called by its users, can be snorted like cocaine or dissolved in a liquid and sprayed on marijuana which in turn is smoked, researchers say. In fact, according to the National Institute on Drug Abuse, PCP can be mixed with virtually anything and consumed.

More commonly, the drug is sprayed on a dried herb such as parsley, rolled into cigarettes on cigarette paper, and then smoked. Used this way, it can produce disorientation, fearful and restless states, or mild euphoria, according to a study shown to legislators by Deputy State's Attorney Clarke.

The drug's adverse effects when taken in other ways, such as by snorting through the nose or orally, range from brief spells of amnesia and possible seizures to prolonged amnesia, vomiting, repeated seizures, and even comatose states, according to Clarke's evidence.

"The whole problem with PCP is that there's so little actually known about it," said Del. American Joe Miedusiewski, who has sponsored another bill that would change the classification of PCP from "Schedule Three" - the category under which a drug that may be prescribed by a physician, such as an amphetamine or barbiturate - to the more restrictive category of "Schedule Two."

"Schedule Two" drugs are defined as having "a high potential for abuse, no accepted medical use in the United States, an da lack of accepted safety for use under medical supervision." Forty-three other drugs are included in this category.

"The effects are bizarre," said Greenville B. Whitman, the former head of a Baltimore city drug abuse clinic, "Man Alive." Whitman said he did not believe that the drug has been shown to be addictive, although, "It always has been considered a drug to avoid. There are no benign effects associated with it."

Miedusiewski's bill to change the classification of PCP was scheduled to come up for a vote late last night.

Notwithstanding the drug's effects, prosecutors have testified that it has become a quick money-maker for those who go into the manufacturing business. "Anyone with a high school chemistry course behind them can make it," Deputy State's Attorney Clarke said at the hearing. "It takes six hours to turn $125 worth of non-contraband drugs into $37,000 worth of contraband drugs," he said.

The federal Drug Enforcement Administration said last year that PCP, which is legally manufactured as an animal tranquilizer, has replaced LSD, the hallucenogen of the 1960s and early 1970s, as the most commonly sought synthetic drug.