FDA-approved usage of morphine sulphate includes moderate to severe pain that may be acute or chronic. Most commonly used in pain management, morphine provides major relief to patients afflicted with pain. Clinical situations that benefit greatly by medicating with morphine include management of palliative/end-of-life care, active cancer treatment, and vaso-occlusive pain during sickle cell crisis. Morphine also has off-label uses for painful conditions. This activity outlines the indications, mechanism of action, methods of administration, important adverse effects, contraindications, monitoring, and toxicity of morphine, so providers can direct patient therapy to optimal outcomes when pain relief is needed.

Objectives:

• Review the mechanism of action of morphine.
• Identify the approved and off-label indications for using morphine.
• Explain the contraindications and adverse events associated with morphine.
• Describe interprofessional team strategies for improving care coordination and communication to properly use morphine to improve patient outcomes in the varied scenarios where it can be effective.

Mechanism of Action

Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors. This drug produces most of its analgesic effects by binding to the mu-opioid receptor within the central nervous system (CNS) and the peripheral nervous system (PNS). The net effect of morphine is the activation of descending inhibitory pathways of the CNS as well as inhibition of the nociceptive afferent neurons of the PNS, which leads to an overall reduction of the nociceptive transmission.

Administration:

Morphine administration can occur through various vehicles. Its administration is most often via the following routes: orally (PO), intravenously (IV), epidural, and intrathecal. Oral formulations are available in both immediate and extended-release for the treatment of acute and chronic pain. Pain that is more severe and not well controlled may be manageable with single or continuous doses of IV, epidural, and intrathecal formulations. Infusion dosing can vary significantly between patients and largely depends on how naive or tolerant they are to opiates. It is interesting to point out that IV morphine formulation is also commonly given intramuscularly (IM). Morphine is also available as a suppository. Morphine is widely used and abused. As a result of this, people have found ways to insufflate (snort) the medication. Morphine is also available as an oral solution and can be administered sublingually. Sublingual morphine is very popular in palliative care.

Adverse effects:

 Among the more common unwanted effects of morphine use is constipation. This effect occurs via stimulation of mu-opioid receptors on the myenteric plexus, which in turn inhibits gastric emptying and reduces peristalsis. Other common side effects include central nervous system depression, nausea, vomiting, and urinary retention. Respiratory depression is among the more serious adverse reactions with opiate use that is especially important to monitor in the postoperative patient population. Other reported side effects include light-headedness, sedation, and dizziness. Patients often report nausea and vomiting, which is why in many emergency departments, morphine administration is with an antiemetic such as ondansetron. Other effects include euphoria, dysphoria, agitation, dry mouth, anorexia, and biliary tract spasm, which is why some physicians will avoid morphine when patients present with right upper quadrant pain and they suspect possible biliary tract pathology. Morphine can also affect the cardiovascular system and reportedly can cause flushing, bradycardia, hypotension, and syncope. It is also important to note that patients can experience pruritis, urticaria, edema, and other skin rashes.