Opioid Analgesics — Adverse Effects & Nursing
Respiratory depression from opioids doesn't announce itself with alarms — it starts with sedation. If you miss the sedation, you miss your window to intervene.
Core Concept
The most dangerous opioid adverse effect is respiratory depression. The progression is predictable: pain relief → sedation → respiratory depression. A sedation scale is your earliest warning tool — increasing drowsiness precedes a falling respiratory rate. Hold the dose and notify the provider if respirations fall below 12 breaths/min or the client becomes difficult to arouse. Beyond respiratory depression, expect constipation in virtually every client on scheduled opioids — it's the one side effect the body never develops tolerance to. Proactive bowel regimens (stool softeners, stimulant laxatives, adequate fluids) start when opioids start. Other predictable effects include nausea/vomiting (worst in the first 24–72 hours, often resolves), urinary retention, orthostatic hypotension, pruritus, and miosis (pinpoint pupils). Nursing priorities: monitor respiratory rate and sedation level before and after each dose, assess pain using a standardized scale, keep naloxone accessible, raise side rails, implement fall precautions due to CNS depression, and teach the client to change positions slowly. Patient teaching must include avoiding alcohol and other CNS depressants, not driving until effects are known, and reporting difficulty breathing or excessive drowsiness immediately.
Watch Out For
Don't confuse sedation (the early warning) with adequate pain relief (the goal) — a client who is increasingly sleepy needs reassessment, not celebration. Students often think constipation resolves with continued use like nausea does — it does not; bowel regimens are lifelong while on opioids. Pruritus from opioids is histamine-mediated, not a true allergy — don't automatically document an allergy for itching alone.
Clinical Pearl
Sedation before desaturation — assess level of consciousness before you count respirations. The sleepy patient is your red flag, not the number on the pulse ox.
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