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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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