Is the patient's hypotension a concern given their scheduled administration of morphine (opioid analgesic) for chronic pain?

From the Guidelines

I strongly recommend administering IV fluids to address the patient's hypotension before administering the scheduled morphine, as the patient's blood pressure of 92/54 is concerning, especially considering morphine's potential to further lower blood pressure through vasodilation and decreased sympathetic tone 1. The patient's hypotension is a significant concern, and administering IV fluids can help increase preload and cardiac output, thereby improving blood pressure.

• For IV fluids, start with a 500mL bolus of normal saline over 1-2 hours.
• Monitor the patient's blood pressure after interventions and before administering morphine.
• If blood pressure remains below 90/60 despite these measures, consider holding the morphine dose and consulting with the prescribing physician about alternative pain management options. Considering midodrine may also be beneficial, as it can increase peripheral vascular resistance to raise blood pressure, but this should be done with caution and careful monitoring of the patient's blood pressure 1. It is essential to prioritize the patient's hemodynamic stability before administering morphine to minimize the risk of adverse effects, such as hypotension and respiratory depression 1.

From the FDA Drug Label

1. 8 Hypotensive Effect Morphine sulfate injection may cause severe hypotension in an individual whose ability to maintain their blood pressure has been compromised by depleted blood volume, shock, impaired myocardial function or concurrent administration of sympatholytic drugs, and drugs such as phenothiazines or general anesthetics Orthostatic hypotension is a frequent complication in single-dose parenteral morphine analgesia in ambulatory patients.

The patient's blood pressure is already low (92/54), and morphine can cause severe hypotension. Caution is advised when administering morphine to this patient.

• Consider the patient's current hypotensive state and the potential for morphine to worsen it.
• The FDA drug label does not provide guidance on ordering fluids or midodrine in this scenario 2.

From the Research

Management of Hypotension

• The patient's blood pressure has been running low, with the last reading being 92/54, and the patient has chronic pain with scheduled morphine administration.
• Considering the patient's hypotension, midodrine could be a potential treatment option, as it is a peripheral alpha-adrenergic agonist used to manage orthostatic hypotension and secondary hypotensive disorders 3, 4.
• Midodrine has been shown to increase standing blood pressure and improve symptoms of orthostatism, such as weakness, syncope, blurred vision, and fatigue, without associated cardiac stimulation 3.

Efficacy and Safety of Midodrine

• Studies have demonstrated that midodrine is at least as effective as other sympathomimetic agents and dihydroergotamine in managing orthostatic or secondary hypotension 3, 4.
• Midodrine is generally well-tolerated, with common adverse effects including piloerection, gastrointestinal disorders, and cardiovascular complaints, which are typically mild and can be controlled by reducing the dosage 3, 4.
• However, the use of midodrine in critically ill patients has shown no significant benefit in accelerating liberation from intravenous vasopressors 5.

Considerations for Midodrine Use

• The optimal dosage and frequency of midodrine administration may vary depending on the patient's condition, with a 10-mg dose prescribed two to three times daily being effective in increasing orthostatic blood pressure and ameliorating symptoms in patients with neurogenic orthostatic hypotension 6.
• Midodrine may be considered for use in patients with hypotension outside of the intensive care unit, including those with vasoplegic conditions such as intradialytic hypotension and refractory ascites 7.