THE MAJOR HAZARDS OF MORPHINE, AS WITH OTHER NARCOTIC ANALGESICS, ARE RESPIRATORY DEPRESSION AND, TO A LESSER DEGREE, CIRCULATORY DEPRESSION, RESPIRATORY ARREST, SHOCK, AND CARDIAC ARREST HAVE OCCURRED.
The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting and sweating. These effects seem to be more prominent in ambulatory patients and in those who are not suffering severe pain. In such individuals, lower doses are advisable. Some adverse reactions may be alleviated in the ambulatory patient who lies down.
Other adverse reactions include the following:
Central Nervous System - Euphoria, dysphoria, weakness, headache, insomnia, agitation, disorientation, and visual disturbances.
Gastrointestinal - Dry mouth, anorexia, constipation, and biliary tract spasm.
Cardiovascular - Flushing of the face, bradycardia, palpitation, faintness and syncope.
Genitourinary - Urinary retention or hesitancy, anti-diuretic effect, and reduced libido and/or potency.
Allergic - Pruritus, urticaria, other skin rashes, edema, and rarely hemorrhagic urticaria.
Treatment of the most frequent adverse reactions:
Constipation - Ample intake of water or other liquids should be encouraged. Concomitant administration of a stool softener and a peristaltic stimulant with the narcotic analgesic can be an effective preventive measure for those patients in need of therapeutics. If elimination does not occur for two days, an enema should be administered to prevent impaction.
In the event diarrhea occurs, seepage around a fecal impaction is a possible cause to consider before antidiarrheal measures are employed.
Nausea and Vomiting - Phenothiazines and antihistamines can be effective treatments for nausea of the medullary and vestibular sources respectively. However, these drugs may potentiate the side effects of the narcotic or the antinauseant.
Drowsiness (sedation) - Once pain control is achieved, undesirable sedation can be minimized by titrating the dosage to a level that just maintains a tolerable pain or pain free state.