Nursing care
Opioid Analgesics: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Opioid analgesics relieve moderate to severe pain by binding mu-opioid receptors, and the nursing priority before every dose is a respiratory assessment. Check respiratory rate and sedation level first, keep naloxone accessible on any unit giving opioids regularly, and start a bowel regimen at the same time as the opioid rather than waiting for constipation to appear.
What it does and why it is prescribed
Opioid analgesics such as morphine, hydromorphone, oxycodone, and fentanyl bind mu-opioid receptors in the central nervous system, blocking pain signal transmission and altering the perception of pain rather than its source. They are prescribed for moderate to severe acute pain, such as post-surgical pain and traumatic injury, and for chronic cancer-related pain where non-opioid options have been insufficient.
Morphine remains a standard for acute severe pain and is also used in palliative care to ease the work of breathing in end-of-life dyspnea. Hydromorphone is roughly five to seven times more potent than morphine by equianalgesic dose and is often chosen when renal impairment limits morphine's use, since morphine's metabolites can accumulate in kidney failure. Choice of agent depends on onset needed, renal and hepatic function, and prior opioid exposure, not on pain severity alone.
Nursing considerations before giving it
Check the respiratory rate and level of sedation before every dose, not just at the start of therapy. A respiratory rate below 12 per minute, or a patient who is difficult to rouse, is a reason to withhold the dose and reassess rather than administer on schedule. This matters more with opioids than with almost any other class, because respiratory depression can develop silently while pain control looks adequate.
Confirm naloxone is available on the unit or at the bedside for any patient on a scheduled or PRN opioid, particularly in the first 24 hours of a new order, after a dose increase, or in an opioid-naive patient. Review the patient's prior opioid exposure and any concurrent CNS depressants, including benzodiazepines and alcohol, since combining these substantially raises the risk of respiratory depression even at otherwise standard opioid doses.
What to monitor
Reassess pain using a validated scale within 30 to 60 minutes of the dose, matched to the route and onset of the drug given, and document the response. Monitor sedation level using a standardised scale such as the Pasero Opioid-Induced Sedation Scale, since sedation deepens before respiratory rate drops and is the earlier warning sign.
Track bowel movements from the first dose, because opioid-induced constipation affects the majority of patients on regular opioid therapy and does not resolve with tolerance the way sedation and nausea often do. Monitor blood pressure for orthostatic hypotension, urinary output for retention, and mental status for confusion, especially in older adults where opioid metabolites clear more slowly.
Side effects versus adverse effects
Expected side effects include constipation, nausea, sedation, and mild pruritus, and these are managed alongside the opioid rather than treated as reasons to stop it. Constipation is addressed prophylactically: a stimulant laxative such as senna is started with the first dose, not after the patient has gone several days without a bowel movement, because prevention is far easier than treating established opioid-induced constipation.
Adverse effects that warrant holding the dose and notifying the prescriber include respiratory depression, oversedation that is difficult to rouse from, hypotension with hemodynamic instability, and signs of an allergic reaction. The distinction the exam and real practice both test is that nausea and constipation are managed through the plan of care, while respiratory depression and unresponsive sedation stop the plan of care until reassessed.
What to hold for and when to call
Hold the dose for a respiratory rate below 12 per minute, oxygen saturation dropping despite supplemental oxygen, or a sedation score indicating the patient is difficult to arouse. Hold for a systolic blood pressure that has dropped significantly from baseline, particularly after a dose increase or in a volume-depleted patient.
Call the prescriber immediately, and prepare naloxone, if respiratory depression is confirmed rather than borderline. Naloxone is titrated in small increments, usually 0.04 to 0.4 mg IV depending on protocol, to reverse respiratory depression while minimising the risk of precipitating acute pain and withdrawal in a patient who is opioid-dependent. Continue to monitor after naloxone administration, since its duration of action is shorter than most opioids and re-sedation can occur once it wears off.
Patient teaching
Teach patients to take the medication as prescribed and not to adjust the dose or interval on their own, and to avoid alcohol and other sedating medications while on opioid therapy. Explain that constipation is expected and that the bowel regimen prescribed alongside the opioid should be taken regularly, not only when symptoms appear, since waiting until constipated makes it harder to treat.
Warn against driving or operating machinery until the effect of a new dose or dose increase on alertness is known. Teach patients and families to recognise excessive sedation, slow or shallow breathing, and confusion as reasons to seek help immediately rather than waiting for the next dose to see if it improves. For patients discharged with opioids, cover safe storage away from children and others, and the plan for disposing of unused doses.
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 should I check before giving an opioid analgesic?
Check the respiratory rate and sedation level first. A respiratory rate below 12 per minute or a patient who is hard to rouse is a reason to hold the dose and reassess before giving it.
Why is constipation treated before it starts with opioids?
Opioid-induced constipation affects most patients on regular opioid therapy and does not resolve with tolerance the way sedation and nausea usually do. A stimulant laxative is started alongside the first opioid dose rather than after constipation develops, because it is much harder to treat once established.
How is naloxone dosed for opioid-induced respiratory depression?
Naloxone is typically titrated in small IV increments, around 0.04 to 0.4 mg depending on protocol, to reverse respiratory depression while limiting the risk of sudden severe pain and withdrawal in an opioid-dependent patient. Reassess after administration, since naloxone's effect can wear off before the opioid's does, allowing re-sedation.
What is the difference between an opioid side effect and an adverse effect?
Side effects such as constipation, mild sedation, and nausea are expected and managed alongside the drug, for example with a bowel regimen or antiemetic. Adverse effects such as respiratory depression or unresponsive sedation require holding the dose and notifying the prescriber, since they signal the drug needs to be stopped or reversed rather than simply managed.
Why might hydromorphone be chosen over morphine?
Hydromorphone is often preferred in patients with renal impairment because morphine's active metabolites can accumulate in kidney failure and prolong or intensify its effects. Hydromorphone is roughly five to seven times more potent than morphine by equianalgesic dose, so dosing is adjusted accordingly.
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