Morphine is a potent opioid analgesic (pain killer) indicated for moderate to severe pain. The drug is helpful for pain relief and sedation which by usually inducing much needed sleep and reduced anxiety, is a benefit for the relief of pain and body’s normal functioning.
As with other similar narcotics, the drug exerts its action on CNS (central nervous system) opioid receptors and other chemical receptors with morphine-like activity found throughout the brain and spinal cord. Respiratory (reduced breathing) depression is produced by its activity on the brain stem centers. It also depresses the cough reflex by its mode of action on the medulla, a part of the brain that affects coughing.
Morphine will slow gastric(stomach) biliary(intestinal) and pancreatic fluid secretions thus slowing digestion, however may cause large intestinal spasm due to increased tone, thus causing constipation, a common side effect also to general anesthetics.
By producing peripheral vasodilation (an opening of the blood vessels in the extremities) morphine can lower blood pressure and result in a fainting or light headedness with abrupt stance (orthostatic hypotension). Patients with bleeding and loss of volume (blood) due to trauma will also experience a further lowering of blood pressure and possible cardiogenic shock (abrupt stoppage of heart beat). It may also produce itching, sweating, and flushing with reddening of the sclera (white portion) of the eyes.
Morphine should be avoided in patients who have had previous reactions to the opioids, patients with reduced respiration, acute or severe bronchial asthmatics unless trained personnel, resuscitative equipment, in a proper environment are available. Patients with documented intestinal problems, with chronic obstructive pulmonary (lung) disease should avoid the analgesic, It should not be given to patients with head injury as it may further increase fluid pressure (cerebrospinal) and obscure some of the neurological signs of pathology, The drug will potentate other CNS depressants such as sedatives, tranquilizers, and alcohol to possibly produce significant profound sedation or coma.
Morphine may produce drug dependence and abuse, and with repeated use physical and psychological dependence can occur, though the former is of no consideration when used to suppress the pain of the terminally ill patient. Withdrawal symptoms will develop with sudden significant reduction in dose or complete cessation. Infants born to mothers of opioid dependency may also be dependent and manifest respiratory depression.
Adverse reactions affect the pulmonary (lung), cardiac, and circulatory system causing possible shock, cardiac arrest and respiratory arrest. The most frequent reactions may include dizziness, lightheadedness, nausea & vomiting, sweating and feeling of euphoria.(general good feeling out of the ordinary) Less common symptoms may be weakness, headache, seizure, uncoordination of muscle, mood alterations including nervousness, apprehension, depression and disorientation, insomnia(difficulty sleeping), visual disturbances- some of which may be reduced by lying down. Dry mouth, diarrhea, abdominal cramps, facial flushing, abnormally low blood pressure, body chills, reduced urine output, itching, rashes, and numbness, tingly sensations in the extremities and edema (swelling.) may also be experienced.
Morphine is eliminated by the body mostly through the renal (kidneys) and because it is metabolized (broken down in the body) to inactive components, dosage usually does not need to be reduced in those patients with renal (kidney) disease however patients should be monitored for possible accumulation to avoid overdose.
Morphine is available orally in both immediate and sustained released dosage forms. The immediate oral forms are both tablet and liquid, as 15mg ( ¼ grain), 30mg (1/2 grain), tablets and oral solution as 20mg per 1cc (5cc== one teaspoonful) in both 30cc and 120cc bottles. The usual adult dose is 5mg to 30mg depend upon pain severity, response, and individual patient’s symptoms and medical conditions every 4 hours. The time released formulation of morphine, MS Contin, is usually prescribed to the patient in need of long term moderate to severe pain relief who had been determined to tolerate the immediate release formulation after some time of treatment.
The sustained formulation is available as 15mg, 30mg, 60mg, 100mg, and 200mg tablets, the usual conversion is by the 15mg tablet or the 30mg tablet dependent upon the patients dosage regiment of the prior drug. The extended formulations should NOT be chewed or crushed to avoid damaging the time release aspect, however, Kadian, a capsule formulation, may be opened and its microcapsules bead sprinkled on food( i.e. applesauce, etc) . Morphine sulfate is also available by injection in 0.5mg/cc, and 1mg/1cc.
MPR, Monthly Prescribing Reference, 2011 Edition, Pain Management Reference
The Rx Consultant, Chronic Nonmalignant Pain, Use of Opioids, vol XI, #5
PDR, Physicians Desk Reference, 2005 Edition 59
My experience in prescribing morphine over my 25 years of podiatry practice since residency has been minimal, however in retail and hospital pharmacy, especially on oncology (cancer) units; the significance of the value of this pain killer, I found to be of great benefit. The patient will have some relief and if possible, as mentioned help to return a resting state and restoration of sleep deprivation due to pain.
See our other pain medication discussions.