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Drug
Information: M
Meperidine | Meprobamate | Methadone |
Methcathinone | Methylphenidate
(Ritalin) | Morphine
Meperidine
Introduced
as an analgesic in the 1930s, meperidine produces effects that are
similar,
but not identical, to morphine (shorter duration of action and reduced
antitussive and antidiarrheal actions). Currently it is used for pre-anesthesia
and the relief of moderate to severe pain, particularly in obstetrics
and post-operative situations. Meperidine is available in tablets,
syrups, and injectable forms under generic and brand name (Demerol®,
Mepergan®, etc.) Schedule II preparations. Several analogues of
meperidine have been clandestinely produced. During the clandestine
synthesis of the analogue MPPP, a neurotoxic by-product (MPTP) was
produced. A number of individuals who consumed the MPPP-MPTP preparation
developed an irreversible Parkinsonian-like syndrome. It was later
found that MPTP destroys the same neurons as those damaged in the Parkinsonian-like
syndrome. It was later found that MPTP destroys the same neurons as
those damaged in Parkinsons Disease.
Meprobamate
Meprobamate
was introduced as an anti-anxiety agent in 1955 and is prescribed primarily
to treat anxiety, tension, and associated muscle spasms. More than
50 tons are distributed annually in the United States under its generic
name and brand names such as Miltown® and Equanil®. Its onset
and duration of action are similar to the intermediate-acting barbiturates;
however, therapeutic doses of meprobamate produce less sedation and
toxicity than barbiturates. Excessive use can result in psychological
and physical dependence. Carisoprodol (Soma®), a skeletal muscle
relaxant, is metabolized to meprobamate. This conversion may account
for some of the properties associated with carisoprodol and likely
contributes to its abuse.
Methadone
German scientists
synthesized methadone during World War II because of a shortage of
morphine. Although chemically unlike morphine or heroin, methadone
produces many of the same effects. Introduced into the United States
in 1947 as an analgesic (Dolophinel), it is primarily used today for
the treatment of narcotic addiction. It is available in oral solutions,
tablets, and injectable Schedule II formulations, and is almost as
effective when administered orally as it is by injection. Methadone's
effects can last up to 24 hours, thereby permitting once-a-day oral
administration in heroin detoxification and maintenance programs. High-dose
methadone can block the effects of heroin, thereby discouraging the
continued use of heroin by addicts under treatment with methadone.
Chronic administration of methadone results in the development of tolerance
and dependence. The withdrawal syndrome develops more slowly and is
less severe but more prolonged than that associated with heroin withdrawal.
Ironically, methadone used to control narcotic addiction is frequently
encountered on the illicit market and has been associated with a number
of overdose deaths.
Methadone Advisory 01/08
Methcathinone
Methcathinone,
known on the streets as "Cat," is a structural analogue of
methamphetamine and cathinone. Clandestinely manufactured, methcathinone
is almost
exclusively sold in the stable and highly water soluble hydrochloride
salt form. It is most commonly snorted, although it can be taken orally
by mixing it with a beverage or diluted in water and injected intravenously.
Methcathinone has an abuse potential equivalent to methamphetamine
and produces amphetamine-like activity. It was placed in Schedule I
of the CSA in 1993.
Methylphenidate
Methylphenidate,
a Schedule II substance, has a high potential for abuse and produces
many of the same effects as cocaine or the amphetamines. The abuse
of this substance has been documented among narcotic addicts who dissolve
the tablets in water and inject the mixture. Complications arising
from this practice are common due to the insoluble fillers used in
the tablets. When injected, these materials block small blood vessels,
causing serious damage to the lungs and retina of the eye. Binge use,
psychotic episodes, cardiovascular complications, and severe psychological
addiction have all been associated with methylphenidate abuse.
Methylphenidate
is used legitimately in the treatment of excessive daytime sleepiness
associated with narcolepsy, as is the newly marketed Schedule IV stimulant,
modafinil (Provigil®). However; the primary legitimate medical
use of methylphenidate (Ritalin®, Methylin®, Concerta®)
is to treat attention deficit hyperactivity disorder (ADHD) in children.
The increased use of this substance for the treatment of ADHD has paralleled
an increase in its abuse among adolescents and young adults who crush
these tablets and snort the powder to get high. Youngsters have little
difficulty obtaining methylphenidate from classmates or friends who
have been prescribed it. Greater efforts to safeguard this medication
at home and school are needed.
Morphine
Morphine is the
principal constituent of opium and can range in concentration from
4 to 21 percent. Commercial opium is standardized to contain 10-percent
morphine. In the United States, a small percentage of the morphine
obtained from opium is used directly (about 15 tons): the remaining
is converted to codeine and other derivatives (about 120 tons). Morphine
is one of the most effective drugs known for the relief of severe pain
and remains the standard against which new analgesics are measured.
Like most narcotics, the use of morphine has increased significantly
in recent years. Since 1990, there has been about a 3-fold increase
in morphine products in the United States.
Morphine is marketed
under generic and brand name products including "MS-Contin®," Oramorph
SR®," MSIR®," Roxanol®," Kadian®," and
RMS®." Morphine is used parenterally (by injection) for preoperative
sedation, as a supplement to anesthesia, and for analgesia. It is the
drug of choice for relieving pain of myocardial infarction and for
its cardiovascular effects in the treatment of acute pulmonary edema.
Traditionally; morphine was almost exclusively used by injection. Today,
morphine is marketed in a variety of forms, including oral solutions,
immediate and sustained-release tablets and capsules, suppositories,
and injectable preparations. In addition, the availability of high-concentration
morphine preparations (i.e., 20-mg/ml oral solutions, 25-mg/ml injectable
solutions, and 200-mg sustained-release tablets) partially reflects
the use of this substance for chronic pain management in opiate-tolerant
patients.
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