Nursing care
Morphine: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated September 2026
Short answer
Morphine is an opioid agonist used for moderate to severe pain that acts on mu receptors in the central nervous system. Before administering, check respiratory rate: below 12 breaths per minute, hold the dose and notify the prescriber. Naloxone reverses overdose. Constipation is near-universal, so a bowel regimen starts with the first dose, not after symptoms appear.
Why this drug and not another
Morphine remains the reference opioid against which other analgesics are measured, and it is the standard choice for moderate to severe pain where non-opioid options have failed or are insufficient: postoperative pain, myocardial infarction, and pain in palliative and end-of-life care. It acts primarily on mu-opioid receptors in the central nervous system, reducing the perception of pain and, at higher doses, producing sedation and respiratory depression.
Its availability in oral, intravenous, subcutaneous, and epidural forms, along with immediate- and extended-release formulations, gives it flexibility that many newer opioids lack. It is also the drug nurses are most likely to encounter across every practice setting, from a surgical floor to hospice, which is why its safety profile is tested so heavily on licensure exams.
Administration and timing
Give oral morphine with or without food; food can reduce nausea in patients who are sensitive to it. IV push doses are administered slowly, generally over four to five minutes, because rapid administration increases the risk of severe respiratory depression and hypotension. Extended-release tablets must never be crushed or split, as doing so destroys the release mechanism and can deliver the full dose at once.
For patients on scheduled dosing for chronic or postoperative pain, give the next dose on time rather than waiting for pain to return to a high level; staying ahead of the pain curve keeps total opioid exposure lower than chasing breakthrough pain. Patient-controlled analgesia pumps are programmed with strict lockout intervals for the same reason, to prevent stacking of doses.
Monitoring parameters
Respiratory rate is the single most important parameter to check before every dose. A rate under 12 breaths per minute means the dose is held and the prescriber is notified before giving more morphine. Sedation level should be assessed alongside respiratory rate, since increasing sedation precedes respiratory depression and is often the earlier warning sign.
Also monitor blood pressure, since morphine causes histamine release and vasodilation that can drop it, and monitor bowel sounds and bowel movement frequency throughout the course of therapy, not just at the start. Pain scores should be reassessed after each dose, using the same scale each time, to judge whether the current dose and interval are adequate.
Adverse effects to report
Respiratory depression is the effect that requires immediate escalation. Naloxone is the reversal agent, given in incremental doses titrated to restore adequate respiration without fully reversing analgesia, and the patient needs continued monitoring afterward because naloxone's duration of action is shorter than morphine's, allowing re-sedation once it wears off.
Constipation is expected with essentially every patient on morphine and is not managed by waiting for it to develop. A stimulant laxative, often paired with a stool softener, is started at the same time as the first opioid dose and continued for the duration of therapy. Other effects to report include urinary retention, pruritus unrelated to true allergy, and confusion or hallucinations in older adults, who are more sensitive to opioid effects at standard doses.
Contraindications and cautions
Use morphine with caution in patients with respiratory conditions such as COPD or severe asthma, where baseline respiratory reserve is already reduced. It is also used cautiously in head injury, since it can mask changes in level of consciousness that would otherwise signal rising intracranial pressure, and in hepatic or renal impairment, where reduced clearance can cause drug accumulation.
It is contraindicated in known hypersensitivity and used with significant caution alongside other CNS depressants, including benzodiazepines and alcohol, because the combination compounds respiratory depression risk. Older adults and opioid-naive patients generally require lower starting doses than opioid-tolerant patients on chronic therapy.
Teaching points the exam tests
Exam questions repeatedly test the respiratory rate threshold, so know that a rate under 12 means hold the dose and notify the provider, not administer and monitor. They also test the bowel regimen timing: constipation prophylaxis starts with the first dose, and a question describing a patient started on morphine without a laxative order is testing whether you catch that gap.
Teach patients to avoid driving or operating machinery until they know how the drug affects them, to rise slowly from sitting or lying to reduce orthostatic hypotension, and to report constipation, confusion, or difficulty breathing rather than tolerating them silently. Patients should also understand that extended-release tablets are swallowed whole, never crushed or chewed.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our pharmacology practice questions are the closest set to what this page covers.
One question from the pharmacology set
A client with heart failure is started on furosemide 40 mg PO daily. Which findings should the nurse report to the provider before administering the next dose? Select all that apply.
Rationale
Furosemide is a loop diuretic, so the two things you are watching are potassium and kidney function. A potassium of 2.9 mEq/L is below the 3.5–5.0 reference range and puts the client at risk for dysrhythmia — hold and report. Muscle cramps with palpitations are the clinical face of that same hypokalemia, so they are reported together, not separately. A creatinine that doubles signals the diuresis has outrun renal perfusion. A blood pressure of 132/78 and a 1 kg loss are the expected response to the drug working, not reasons to hold it.
Answer: A, D, E
Common questions
What respiratory rate should hold a morphine dose?
A respiratory rate below 12 breaths per minute means the dose is held and the prescriber is notified before any further morphine is given.
What reverses a morphine overdose?
Naloxone, given in titrated doses to restore adequate breathing. Because naloxone's effect wears off faster than morphine's, the patient needs continued monitoring for re-sedation.
Does constipation from morphine go away on its own?
No, tolerance does not develop to the constipating effect the way it does to sedation. A bowel regimen, usually a stimulant laxative with a stool softener, is needed for as long as the patient takes morphine.
Can extended-release morphine tablets be crushed?
No. Crushing or splitting destroys the extended-release mechanism and can deliver the entire dose at once, sharply raising overdose risk.
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