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Morphine is an opioid administered for acute and chronic pain conditions. The advantage of intrathecal (IT) morphine over intravenous (IV), oral (PO), or transdermal (TD) opiates is due to its delivery into the subarachnoid space with direct access to opiate receptors and ion channels. It may be administered as a bolus, an infusion, or a combination of the two. This activity describes the mode of action of intrathecal morphine, including mechanism of action, pharmacology, adverse event profiles, eligible patient populations, monitoring, and highlights the role of the interprofessional team in the management of conditions where intrathecal morphine offers an advantage. Objectives: Summarize the indications for intrathecal morphine. Explain the differences between intrathecal morphine administration and other modes of administration. Review the contraindications and adverse events associated with intrathecal morphine administration. Outline the importance of collaboration and communication among interprofessional team members to improve outcomes and treatment efficacy for patients receiving treatment with intrathecal morphine. Access free multiple choice questions on this topic.

Naloxone, the antidote for an overdose of opiates, is a competitive mu-opioid–receptor antagonist that reverses all signs of opioid intoxication.  It can be given parenterally, intranasally, intramuscularly, subcutaneously, or via an endotracheal tube.  The initial dose of naloxone for overdose is 0.04 mg (if given intravenously), which can be increased every 2 minutes to a maximum of 15 mg. The onset of action is generally less than 2 minutes when given intravenously. The duration of action is 20 to 90 minutes, which is shorter than the opiate effects, often rendering redosing or infusion necessary.

Intrathecal morphine is usually only administered by an oncologist, anesthesiologist, or a pain specialist. Typically, intrathecal morphine is more likely to benefit patients with nociceptive or neuropathic pain that is well localized and responsive to systemic opioids. This pain may or may not be cancer-related. Additionally, intrathecal opiates should be avoided or minimized in patients with pulmonary disease, obstructive sleep apnea, or substance abuse. Intrathecal administration of morphine through implantable pumps should be carefully considered and likely avoided in patients with cancer-related pain whose life expectancy is less than three months as it takes time to reach a suitable dosing regimen, and this must be weighed against the risks of the pump.[10] Patients with intrathecal morphine pumps need to be monitored by the nurse. The nurse should always have an order for naloxone in case the patient shows signs of opioid toxicity [1]. The use of intrathecal morphine requires an interprofessional healthcare team. The clinician (including pain specialists or oncologists) will initiate treatment with intrathecal morphine, but a pharmacist should also have involvement to verify appropriate dosing and should also check for potential drug interactions (e.g., CYP3A4 agonists/antagonists). Nursing administering the drug should understand proper administration and dosing, as well as the signs of toxicity, and report any concerns to the clinician promptly. This type of interprofessional team approach optimizes intrathecal morphine administration, results, and safety, leading to better patient outcomes for pain control. [Level 5]