Morphine biliary tract effects

Meperidine differs from morphine in that it has far less antitussive effect and little constipative effect. The drug is particularly useful in cancer patients and in pulmonary patients, in whom the cough reflex must remain intact. However, it does have more seizure-inducing activity than morphine. Although meperidine produces spasms of the biliary tract and colon, such spasms are of shorter duration than those produced by morphine. 

Meperidine has replaced morphine to a large extent in medical practice because of the physician s reluctance to use an opiate and the belief that meperidine manifests less undesirable side effects than does morphine. However, both of these assumptions are ill founded. Addiction to meperidine is much less amenable to treatment than is addiction to morphine. Meperidine, similar to morphine and codeine, causes spasm of the upper gastrointestinal tract and typical attacks of biliary colic in biliary tract disease. Meperidine, in doses giving an equal analgesic effect, induces as much respiratory depression as does morphine. Similar to morphine, it also crosses the placental barrier and must therefore be used cautiously in the latter stages of labor. 

Smooth muscle is relaxed. In the gastrointestinal tract there is reduction of tone and peristalsis. Muscle spasm of the intestinal tract induced by morphine is reduced, but such spasm in the biliary tract is not significantly affected. Atropine relaxes bronchial muscle, an effect that is useful in some asthmatics. Micturition is slowed and urinary retention may be induced especially when there is pre-existing prostatic enlargement. 

BILIARY TRACT After the subcutaneous injection of 10 mg morphine sulfate, the sphincter of Oddi constricts, and the pressure in the common bile duct may rise more than tenfold within 15 minutes this effect may persist for 2 hours or more. Fluid pressure also may increase in the gallbladder, producing symptoms that vary from epigastric distress to typical biliary cohc. All opioids can cause biliary spasm. Atropine only partially prevents morphine-induced biliary spasm, but opioid antagonists prevent or relieve it. Nitroglycerin (0.6-1.2 mg) administered sublingually also decreases the elevated intrabiliary pressure. 

UNTOWARD EFFECTS AND PRECAUTIONS Morphine and related opioids produce a wide spectrum of unwanted effects, including respiratory depression, nausea, vomiting, dizziness, mental clouding, dysphoria, pruritus, constipation, increased pressure in the biliary tract, urinary retention, hypotension, and rarely dehiium. Increased sensitivity to pain after analgesia has worn off also may occur. 

The narcotic analgesics tend to produce euphoria which is an important factor in their addietive property which limits their use. Other limitations include respiratory depression, decreased gastrointestinal motility leading to constipation, increase biliary tract pressure and pruritus due to histamine release. Beeause of these setbacks in the use of morphine there has been a eonstant effort to develop analgesies with fewer side-effects and minimal addictive actions. 

Morphine decreases the propulsive contractions of the gastrointestinal tract, and biliary and pancreatic secretions are reduced. The end result, especially when morphine is administered over extended time periods, is constipation. Morphine-induced spasms of the sphincter of Oddi have been observed. However, the clinical significance of such an occurrence should be assessed on an individual basis. Although morphine s effect on the urinary bladder varies, urinary... 

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