Types of Pain
Classify pain by duration and by source — it guides the right treatment.
By Duration
- Acute pain: recent, time-limited, protective. Often shows a sympathetic response — increased heart rate, blood pressure, and sweating. Resolves as healing occurs.
- Chronic pain: lasts beyond expected healing (often > 3–6 months). May have no outward signs — normal vital signs do not mean no pain.
By Source
- Nociceptive — somatic: from skin, muscle, bone; usually well-localized, aching or throbbing.
- Nociceptive — visceral: from internal organs; diffuse, deep, cramping, hard to pinpoint.
- Neuropathic: from nerve damage; burning, tingling, shooting, or electric (e.g., diabetic neuropathy, phantom limb pain). Responds to adjuvants more than to typical analgesics.
In acute pain you may see a racing heart and high blood pressure, but in chronic pain the body adapts and vital signs are often normal. Never use "stable vital signs" to dismiss a patient's report of pain — believe the patient.
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Pain Assessment
Pain is subjective — the patient's report is the gold standard.
The classic principle: "Pain is whatever the patient says it is, occurring whenever they say it does." Self-report is the most reliable indicator. Believe the patient, and reassess after every intervention (around 30–60 minutes, or at the medication's peak).
Common Pain Scales
- Numeric (0–10): most older children and adults who can self-report.
- Wong-Baker FACES: cartoon faces; children about age 3+ and some adults.
- FLACC: infants, young children, and nonverbal patients — observe Face, Legs, Activity, Cry, Consolability.
- PAINAD: patients with advanced dementia.
PQRST — A Pain History Tool
- P — Provocation/Palliation (what makes it better/worse)
- Q — Quality (sharp, dull, burning, cramping)
- R — Region/Radiation (where, does it travel)
- S — Severity (0–10 rating)
- T — Timing (onset, duration, pattern)
Can't self-report (infant, nonverbal, sedated)? Use FLACC (behavioral observation). Young child who can point? Use FACES. Alert adult? Use the 0–10 numeric scale. Picking the right tool for the patient is a common exam question.
? A 2-year-old is post-op and crying. Which pain scale is most appropriate?
Non-Opioid Analgesics
First-line for mild pain — but each has a key safety ceiling.
- Acetaminophen(Tylenol)
- Mild pain, fever. No anti-inflammatory effect. Max ~3,000–4,000 mg/day; hepatotoxic. Caution in liver disease/alcohol use. Watch hidden acetaminophen in combo products.
- NSAIDsibuprofen, naproxen, ketorolac
- Mild-moderate pain, inflammation, fever. GI bleeding and ulcer risk (take with food), kidney impairment, increased bleeding. Avoid in PUD and renal disease.
- Aspirin
- Pain, fever, antiplatelet. Bleeding risk; avoid in children (Reye's syndrome) with viral illness.
Acetaminophen is safe at recommended doses but the leading cause of acute liver failure when overdosed. Stay at or below the daily maximum, lower it in liver disease and alcohol use, and teach patients that many OTC cold medicines and prescription pain pills already contain it — doubling up is easy and dangerous.
Opioid Analgesics
For moderate-to-severe pain — powerful and effective, with predictable side effects.
Common opioids include morphine, hydromorphone (Dilaudid), fentanyl, oxycodone, hydrocodone, and codeine. They relieve moderate to severe pain by acting on opioid receptors in the central nervous system.
Common Side Effects
- Respiratory depression — the most serious (covered next).
- Sedation — often precedes respiratory depression.
- Constipation — nearly universal and does not improve over time.
- Nausea/vomiting, itching (histamine release), urinary retention, hypotension.
- Pinpoint pupils (miosis) — a classic sign of opioid effect/overdose.
With ongoing use, patients become tolerant to sedation, nausea, and even respiratory depression — but never to constipation. That's why a stool softener/laxative bowel regimen is started alongside scheduled opioids, every time.
Opioid Safety
Respiratory depression is the danger — know the parameters and the antidote.
- Monitor respiratory rate and sedation before and after dosing. Rising sedation is an early warning.
- Hold the dose and notify the provider if respirations fall below the ordered parameter (commonly < 12/min).
- Naloxone (Narcan) is the opioid antidote — it rapidly reverses respiratory depression and sedation. Have it available for high-risk patients.
- Start a bowel regimen (stool softener/laxative) to prevent constipation.
- Assess fall risk — opioids cause sedation, dizziness, and hypotension.
Before giving an opioid, check the respiratory rate. If it's below the ordered limit (often 12/min) or the patient is hard to arouse, hold the dose and notify the provider — do not give it. After dosing, the most important monitoring is respiratory rate and level of sedation. Naloxone reverses an opioid overdose.
? A patient on morphine has a respiratory rate of 10/min and is difficult to arouse. What is the priority action?
Adjuvants & Non-Drug Methods
Other medications and comfort measures that boost pain control.
Adjuvant Medications
- Anticonvulsants (gabapentin, pregabalin) — neuropathic pain.
- Antidepressants (duloxetine, tricyclics) — neuropathic and chronic pain.
- Corticosteroids — inflammation and certain cancer pain.
- Muscle relaxants — musculoskeletal/spasm pain.
Non-Pharmacologic Methods
- Heat (relaxes muscle, increases blood flow) and cold (reduces swelling, numbs) — follow time limits and protect skin.
- Distraction, relaxation, guided imagery, music.
- Massage, repositioning, TENS unit.
- These complement medication and are excellent "what else can the nurse do" answers.
Burning, shooting, "electric" nerve pain often responds poorly to standard analgesics and better to gabapentin/pregabalin or certain antidepressants. If a question describes diabetic neuropathy or post-herpetic pain, the adjuvant is usually the best answer.
WHO Ladder & PCA
A step approach to dosing, and the safety logic behind patient-controlled analgesia.
WHO Analgesic Ladder
For constant pain, give analgesics around the clock (ATC) rather than only PRN, to stay ahead of the pain.
Patient-Controlled Analgesia (PCA)
- The patient self-administers small IV doses by pressing a button.
- Only the patient presses the button — never family or staff ("PCA by proxy" is unsafe).
- A lockout interval limits how often a dose is delivered, preventing overdose.
- Monitor respiratory rate and sedation routinely.
The safety of a PCA depends on the patient being awake enough to press it themselves. If a family member presses it while the patient sleeps, that built-in protection is gone and an overdose can occur. Teach the family: support and encourage, but never push the button for the patient.
Special Populations
Adjust the approach for older adults, children, and patients with addiction concerns.
- Older adults: often under-treated; more sensitive to opioids. "Start low, go slow." Avoid meperidine (Demerol) — its metabolite can cause seizures, especially in the elderly and those with kidney problems.
- Children: use age-appropriate scales (FLACC, FACES); pain is often underestimated.
- Addiction concerns: fear of addiction leads to under-treatment. Physical dependence and tolerance are expected with long-term opioids and are not the same as addiction. Treat reported pain appropriately.
Aging changes how the body handles drugs, so older adults need careful, lower starting doses and close monitoring — but they should still be treated for pain. Skip meperidine (Demerol) in this group because of its seizure-causing metabolite.
Frequently Asked Questions
Common student questions on this topic.
What is the gold standard for assessing pain?
Which pain scale is used for a young child or a nonverbal patient?
What is the most dangerous side effect of opioids, and what is the antidote?
Why do patients on opioids need a bowel regimen?
What is the maximum daily dose of acetaminophen and why?
Who is allowed to press the button on a PCA pump?
Quick-Reference Cheatsheet
Every key point from this guide on a single printable page.
Pain Management Cheatsheet
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