PHARMACOLOGY AND ACTIONS:
- Morphine sulfate is a
- narcotic with potent analgesic and hemodynamic properties. It exerts its analgesic effects on the
- central nervous system, simultaneously inducing drowsiness, mental clouding and
- mood changes. Morphine has several
- hemodynamic actions of considerable importance.
- 1. It increases venous capacitance and thereby
- pools blood peripherally and decreases its return (reduced preload). This assists in relieving pulmonary
- congestion, reduces left ventricular and diastolic dimensions, and myocardial
- wall stress. These all result in
- decreased myocardial oxygen requirement.
- 2. Reduces systemic vascular resistance at the
- arteriolar level (reduced after load).
- This reduction in afterload also tends to decrease myocardial oxygen
- requirement. Central sedative effects of
- morphine also will reduce myocardial oxygen requirements and the chance of
- malignant arrhythmias due to reduction of apprehension and fear in
- patients. The hemodynamic effects of
- Morphine are probably mediated through the central nervous system by a
- sympatholytic mechanism. Given
- intravenously, the onset of action is prompt (2-3 minutes), peaks at 7 - 10
- minutes, and last 3 - 5 hours.
- 1. Severe chest pain unaffected by respirations
- or body movements with suspected ischemic cardiac pain unresponsive to
2. Pulmonary edema.
- 3. Severe pain associated with burn or extremity
- injuries not affecting respiratory or hemodynamic status.
1. Known allergy to morphine.
2. Volume depletion.
4. Undiagnosed head trauma.
5. CNS Trauma, such as paralysis.
MORPHINE SULFATE CONTINUE
- Morphine sulfate causes predictable
- respiratory depression. This is
- quickly reversible with naloxone (Narcan).
- Respiratory depression is much more likely to occur in patients
- with pre-existing respiratory insufficiency (COPD).
- Use with caution in undiagnosed
- abdominal pain or potential surgical emergencies, e.g. appendicitis or
- acute abdomen.
- Naloxone (Narcan) and
- respiratory support must be at hand when administering morphine.
- 1. Morphine
- should be given by titration of small intravenous doses at frequent intervals
- until the desired response is achieved.
- There is considerable variation from patient to patient in the amount of
- drug required to acquire the given effect.
- 2. A dose of
- 2-5 mg IV is given and repeated at 5-30 minute intervals until the desired effect
- has been achieved. Total dose of 20mg
- with Physician Consult required exceeding 20mg.
- 3. Pediatric
- Dose: Pediatrics less than 50 kg,
- 0.1mg/kg IV.
- 4. Vital
- signs should be taken with particular attention to blood pressure and
- respiratory rate after every incremental dose is administered. The end points of administration should be:
A. Achievement of desired effects.
B. Blood pressure less than 90 mmHg systolic
C. Respiratory rate less than 12.
SIDE EFFECTS AND SPECIAL NOTES:
1. Respiratory depression, nausea and vomiting.
- 2. The analgesic effect of morphine should not
- be gauged solely by the total elimination of pain. More importantly, morphine reduces the
- perception of pain.
- 3. Hypotension may develop as a consequence of
- the hemodynamic effect of morphine, especially in older patients, volume
- depleted patients, or patients who have required elevated systemic vascular
- resistance for the maintenance of their blood pressure. Hypotension is usually responsive to naloxone
- administration and the Trendelenburg position.
- If not, contact medical control, prepare for cautious fluid challenge
- with 100 cc of Normal Saline.
- 4. Morphine has a high tendency for
- addiction/abuse and is classified as a schedule II drug under the Controlled
- Substances Act of 1970.