Morphine Sulfate

Morphine

Class:  Opioid analgesic
Actions:
  • Dilation of veins; moderate dilation of arteries
  • Analgesia through interaction with mu receptor sites
Indications:
  • Chest pain associated with acute coronary syndrome
  • Acute cardiogenic pulmonary edema
Pharmacokinetics:
  • Onset: 2-4 minutes for IV boluses
  • Peak: 20 minutes for IV boluses
  • Half-Life: 2-3 hours
  • Metabolism:  primarily metabolized by the liver
Adverse Effects:
  • Drowsiness, mental clouding, anxiety reduction, euphoria, disorientation
  • Orthostatic hypotension
  • Respiratory depression
  • Constipation
  • Urinary retention (sphincter constriction)
  • Cough suppression
  • Biliary colic (constriction of the Sphincter of Oddi)
  • Nausea, emesis
  • Miosis (constricted pupils)
Signs of Toxicity:
  • Respiratory depression–apnea
  • Somnolence–unresponsive to physical stimulation
  • Hypotension
  • Pinpoint pupils
Contraindications:
  • Hypersensitivity to opiates
  • Elevated intracranial pressure (head injuries)
  • Convulsive disorders
  • Acute alcoholism
  • Acute bronchial asthma
  • Prostatic hypertrophy
  • Post biliary tract surgery
  • Pancreatitis
  • Acute ulcerative colitis
  • Addison's disease
  • Hypothyroidism
Dosages & Routes:
  • PO:  10-30 mg q 4 hours (adults)
  • Intravenous: 2 – 10 mg slow IV push q 4 hour prn; (cardiac) 2 – 4 mg slow IV push, repeat dose at 5 – 15 minute intervals
  • Intramuscular (IM):  (not appropriate for cardiac intervention) 5 – 20 mg IM q 4 hours prn
Nursing Implications:
  • Monitor blood pressure prior to administration.  Hold if systolic BP < 100 mm Hg or 30 mm Hg below baseline.
  • Monitor patient's respiratory rate prior to administration.
  • Reassess pain after administration of morphine.
  • Monitor for respiratory depression and hypotension frequently up to 24 hours after administration of morphine.
  • Place call light signal close to patient.  Accompany patient if need to get out of bed to minimize risk of falls.
  • Drug interactions:  CNS depression potentiated with other narcotics, alcohol, barbiturates, & benzodiazepines.
  • Drug interactions:  Anticholinergic effects potentiated with antihistamines, tricyclic antidepressants, and atropine–these can worsen constipation and urinary retention.
  • Drug interactions:  Hypotension can result if combined with anti-hypertensive drugs or vasodilators.
  • Treatment for overdose includes ventilatory support (manual ventilation with a bag-valve-mask resuscitator) and administration of an opiate antagonist (e.g., naloxone).
  • Tolerance, a condition requiring larger doses to achieve the same therapeutic effect, can result from prolonged use.
  • Physical dependence, resulting from prolonged use, may create the risk of withdrawal symptoms if drug is completely discontinued.
  • Avoid alcohol and other CNS depressants while under the influence of morphine.
  • Avoid tasks requiring alertness like driving and operating heavy machinery while under the influence of morphine.

 

References:

American Heart Association. (2006). Handbook of Emergency Cardiac Care (p. 58). Salem, MA: AHA.

Dirks, J.L. (2010) Cardiovascular therapeutic management.  In L.D. Urden, K.M. Stacy, & M.E. Lough's (Eds.) Critical care nursing: Diagnosis and management (6th ed., p. 438).  St. Louis: Mosby Elsevier.

Lehne, R.A. (2010). Pharmacology for nursing care (7th ed., pp. 262-269, 621).  St. Louis: Saunders Elsevier.

Wilson, B.A., Shannon, M.T., Shields, K.M., & Stang, C.L. (2007).  Prentice Hall Nurse's Drug Guide 2007 (pp. 1108-1111).  Upper Saddle River, NJ: Pearson Prentice Hall.

 

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