Morphine

Synopsis

The Morphine Molecule

Morphine is naturally occurring substance in the opium poppy, Papaver somniferum. It is a potent narcotic analgesic, and its primary clinical use is in the management of moderately severe and severe pain. After heroin, morphine has the greatest dependence liability of the narcotic analgesics in common use.

Morphine is administered by several routes (injected, smoked, sniffed, or swallowed); but when injected particularly intravenously, morphine can produce intense euphoria and a general state of well-being and relaxation. Regular use can result in the rapid development of tolerance to these effects. Profound physical and psychological dependence can also rapidly develop, and withdrawal sickness upon abrupt cessation of heroin use; many of the symptoms resemble those produced by a case of moderately severe flu.

Morphine is infrequently encountered in the North American street drug culture. However, mainly because of its availability in hospitals, there have been several documented cases of morphine dependence among health professionals.

Drug Source

Morphine is isolated from crude opium, which is a resinous prep of the opium poppy, Papaver somniferum.

Trade Name

Roxinal, MS Contin, Morphine Sulfate

Street Names

"M", morph, Miss Emma

Drug Combinations

Use of morphine plus cocaine, as well as of morphine plus methamphetamine, has been reported. However, such combinations are not frequently encountered.

Medical Uses

• symptomatic relief of moderately severe to severe pain;
• relief of certain types of difficult or labored breathing;
• suppression of severe cough (rarely);
• suppression of severe diarrhea (e.g., that produced by cholera).

Physical Appearance

Morphine is legally available only in the form of its water-soluble salts. Most common are morphine sulfate and morphine hydrochloride. Both are fine white crystalline powders, bitter to the taste. Both are soluble in water and slightly soluble in alcohol.

Dosage

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Medical

For moderate to severe pain the optimal intramuscular dosage is considered to be 10 mg per 70 kg body weight every four hours. The typical dose range is from 5 to 20 mg every four hours, depending on the severity of the pain. The oral dose range is between 8 and 20 mg; but with oral administration morphine has substantially less analgesic potency (approximately one-tenth of the effect produced by subcutaneous injection) because it is rapidly destroyed as it passes through the liver immediately after absorption. The intravenous route is employed primarily for severe post-operative pain or in an emergency; in this case the dose range is between 4 and 10 mg, and the analgesic effect ensues almost immediately.

Nonmedical

Irregular or intermittent users (who are not substituting the drug for another narcotic analgesic) may start and continue to use doses within the therapeutic range (e.i., up to 20 mg). However, regular users who employ morphine for its subjectively pleasurable effects frequently increase the dose as tolerance develops. To take several hundred milligrams per day is common, and there are reliable reports of up to four or five grams (4000 - 5000 mg) per day.

Routes Of Administration

Morphine may be taken orally in tablet form, and can also injected subcutaneously, intramuscularly, or intravenously; the last is the route preferred by those who are dependent on morphine.

Short Term Use

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Low Doses (single doses of 5 - 10 mg administered by S.C or IM injection in non-tolerant users)

CNS, behavioral, subjective:

suppression of the sensation of and emotional response to pain; euphoria; drowsiness, lethargy, relaxation; difficulty in concentrating; decreased physical activity in some users and increased physical activity in others; mild anxiety or fear; pupillary constriction, blurred vision, impaired night vision, suppression of cough reflex.

Respiratory:

slightly reduced respiratory rate.

Gastrointestinal:

nausea and vomiting; constipation; loss of appetite; decreased gastric motility.

Other:

slight drop in body temperature; sweating; reduced libido; prickly or tingling sensation on the skin (particularly after intravenous injection).

Duration

4 - 5 hours

Dependency Potential

high, continued use results in both psychological and physical dependency