Medical Pharmacology Chapter 13:  Clinical Use: opioid analgesics in pain management

•  Management/Treatment of Opioid Overdosage

  • Diagnosis:

    • May be straightforward (known addict; miosis; needle marks)

    • May be difficult (comatose patients -- no history available)

  • Treatment:

    • Intravenous naloxone-- rapid coma reversal if due to opioid overdose (no effect if coma is due to overdose with a sedative hypnotic)

•   Contraindications/Therapeutic Cautions

  • For patients receiving the opioid agonists

    • Do not administer a mixed agonist-antagonist (e.g. pentazocine): withdrawal may be precipitated;

    • Diminishment of analgesia may occur

  •  In patients with head injuries: opioids may induce a further increase in intracranial pressure

  • Pregnancy

    •  Pregnant women chronically using opioids:

      • Fetus may become physiologically dependent in utero

      • Withdrawal symptoms may appear in the early postpartum time frame

      • Management of fetal withdrawal symptoms:

        • Mild: management with diazepam

        • More severe: oral methadone; tincture of opium (paregoric)

  • Patients with impaired lung function

    • Acute respiratory failure: may be precipitated by opioid-mediated respiratory depression

  • Patients with impaired hepatic or renal function

    • Half-life may be prolonged in patients with impaired renal function; e.g. morphine and its active metabolite morphine-6-glucuronide may accumulate (reduction in dosage)

    • Since the liver is the primary metabolic site for morphine and related compounds,  use in patients with pre-hepatic coma may be inappropriate

  •  Patients with endocrine disorders

    • Adrenal-insufficiency (Addison's disease)or hypothyroidism (myxedema): prolonged, exaggerated opioid responses

1. Way, W.L., Fields, H.L. and Way, E. L. Opioid Analgesics and Antagonists, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 496-515.

2. Schuckit, M.A. and Segal D.S., Opioid Drug Abuse and Dependence, In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp 2508-2512;

3. Coda, B.A. Opioids, In Clinical Anesthesia, 3rd Edition (Barash, P.G., Cullen, B.F. and Stoelting, R.K.,eds) Lippincott-Ravin Publishers, Philadelphia, New York, 1997, pp 329-358.