Analgesics fact sheet | Encyclopedia MDPI

Analgesics fact sheet: History

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Subjects: Critical Care Medicine

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Analgesics Fact Sheet Overview

This guide provides a structured, decision-oriented approach to the use of analgesics across common categories: Acetaminophen, NSAIDs, Opioids, Antiepileptics, Antidepressants, and Corticosteroids. It outlines:

When to Use: Specific pain types, conditions, and scenarios where each drug class is effective.
When to Avoid: Key contraindications and risk factors for each category.
Dosages: Standard therapeutic dosing to ensure safe and effective treatment.

Designed for quick clinical reference, this fact sheet emphasizes practical applications, focusing on analgesic choice tailored to pain type, patient comorbidities, and safety considerations.

analgesia
Pain management
Factsheet

Q&A Summary for Analgesics

1. When should Acetaminophen be used?

For mild to moderate somatic and visceral pain.
Treats fever, headache, muscle, and general pain.
Available in oral, liquid, rectal, and intravenous forms.

2. When should Acetaminophen be avoided?

Patients with liver impairment.
Avoid exceeding 4 grams/day (monitored) or 3 grams/day (unmonitored) due to risk of hepatic necrosis.

3. When should NSAIDs be used?

For mild to moderate pain associated with inflammation (musculoskeletal).
Available in oral, liquid, topical, and intravenous forms.

4. When should NSAIDs be avoided?

In patients with bleeding risks (e.g., on anticoagulants, low platelets, prior GI bleeding).
Avoid in renal dysfunction, diabetes, CHF, or concurrent corticosteroid use.

5. When should Opioids be used?

For moderate to severe somatic, visceral, and neuropathic pain.
Essential for cancer pain management.
Available in oral, liquid, transdermal, intravenous, and rectal forms.

6. When should Opioids be avoided?

Persistent non-cancer pain without serious illness unless managed by a pain specialist.

7. When should Antiepileptics be used?

For moderate to severe neuropathic pain (e.g., gabapentin, pregabalin).
Adjust dose in renal failure patients.

8. When should Antidepressants be used?

For neuropathic pain and mood disorders, especially tricyclic antidepressants (TCA) and serotonin-norepinephrine reuptake inhibitors (SNRIs).

9. When should Antidepressants be avoided?

Use TCAs with caution in older patients or those with cardiac disease.

10. When should Corticosteroids be used?

For moderate to severe pain, including capsular stretch pain, bone pain, or raised intracranial pressure.
Also helps with appetite and fatigue.

11. When should Corticosteroids be avoided?

Avoid combining with NSAIDs due to increased GI bleeding risk.

Category	When to Use	When to Avoid	Notes
Acetaminophen	Mild to moderate pain; fever, headache, muscle pain.	Liver impairment; doses >4 g/day monitored or >3 g/day unmonitored.	No anti-inflammatory effect.
NSAIDs	Pain with inflammation, e.g., arthritis.	GI bleeding, renal dysfunction, CHF, elderly, anticoagulants, corticosteroid use.	No NSAID is proven superior in efficacy or safety. Celecoxib is the only Cox-2 inhibitor.
Opioids	Severe pain (somatic, visceral, neuropathic), cancer pain.	Long-term non-cancer pain unless under specialist care.	Side effects manageable (constipation, nausea). Taper on discontinuation.
Antiepileptics	Neuropathic pain (e.g., gabapentin, pregabalin).	Use caution in renal failure.	Causes sedation, ataxia, edema. Effective in some neuropathic pain syndromes.
Antidepressants	Neuropathic pain, mood disorders (e.g., TCAs, SNRIs).	Caution in older adults or cardiac disease (QT prolongation).	SSRIs are ineffective for pain.
Corticosteroids	Severe pain (capsular stretch, bone pain, raised ICP).	NSAID co-use (GI bleeding).	Significant side effects (myopathy, hyperglycemia, adrenal insufficiency).

Now with dosages

Q&A Summary for Analgesics (with Dosages)

1. When should Acetaminophen be used, and what is the recommended dosage?

Use: For mild to moderate somatic and visceral pain, fever, headache, muscle, and general pain.
Dosage:
- Standard dose: 325–650 mg every 4–6 hours or 1,000 mg every 6–8 hours.
- Maximum dose: 4 g/day (monitored) or 3 g/day (unmonitored).

2. When should Acetaminophen be avoided?

Avoid in patients with liver impairment or when exceeding recommended daily doses due to hepatotoxicity risks.

3. When should NSAIDs be used, and what are common dosages?

Use: For pain with inflammation, e.g., arthritis or musculoskeletal conditions.
Dosages:
- Ibuprofen: 200–800 mg every 6–8 hours (max 3.2 g/day).
- Naproxen: 250–500 mg twice daily (max 1,500 mg/day).
- Celecoxib (Cox-2 inhibitor): 100–200 mg once or twice daily (max 400 mg/day).

4. When should NSAIDs be avoided?

Avoid in patients with GI bleeding, renal dysfunction, CHF, or concurrent corticosteroid use.

5. When should Opioids be used, and what are appropriate dosages?

Use: For moderate to severe somatic, visceral, or neuropathic pain.
Dosages:
- Morphine: 5–10 mg IV every 4 hours as needed; 15–30 mg oral every 4 hours as needed.
- Hydrocodone/Acetaminophen (e.g., Norco): 5–10 mg hydrocodone every 4–6 hours (acetaminophen included counts toward the daily max).
- Oxycodone: 5–15 mg oral every 4–6 hours as needed.
- Fentanyl (transdermal): 12–100 mcg/hour, changed every 72 hours.

6. When should Opioids be avoided?

Avoid in long-term non-cancer pain without specialist oversight.

7. When should Antiepileptics be used, and what are common dosages?

Use: For moderate to severe neuropathic pain, e.g., diabetic neuropathy.
Dosages:
- Gabapentin: Initial dose 300 mg at bedtime, titrate to 300–600 mg three times daily (max 3,600 mg/day).
- Pregabalin: 75 mg twice daily, titrate to 150 mg twice daily (max 600 mg/day).

8. When should Antidepressants be used, and what are common dosages?

Use: For neuropathic pain and mood disorders.
Dosages:
- Amitriptyline (TCA): Start at 10–25 mg at bedtime, increase to 75–150 mg/day as tolerated.
- Duloxetine (SNRI): 30 mg daily, titrate to 60 mg daily.

9. When should Antidepressants be avoided?

Use caution with TCAs in older adults or those with cardiac disease due to QT prolongation.

10. When should Corticosteroids be used, and what are appropriate dosages?

Use: For severe pain (e.g., capsular stretch, bone pain, or raised intracranial pressure).
Dosages:
- Dexamethasone: 4–10 mg daily (long-acting).
- Prednisone: 10–40 mg daily (varies based on indication).

11. When should Corticosteroids be avoided?

Avoid combining with NSAIDs due to increased GI bleeding risk.

Category	When to Use	When to Avoid	Common Dosages
Acetaminophen	Mild to moderate pain; fever, headache, muscle pain.	Liver impairment; doses >4 g/day monitored or >3 g/day unmonitored.	325–650 mg every 4–6 hours; max 4 g/day (monitored).
NSAIDs	Pain with inflammation, e.g., arthritis.	GI bleeding, renal dysfunction, CHF, elderly, anticoagulants, corticosteroid use.	Ibuprofen 200–800 mg every 6–8 hours (max 3.2 g/day); Naproxen 250–500 mg BID (max 1.5 g).
Opioids	Severe pain (somatic, visceral, neuropathic), cancer pain.	Long-term non-cancer pain unless under specialist care.	Morphine 5–10 mg IV q4h or 15–30 mg PO q4h; Fentanyl patch 12–100 mcg/hour q72h.
Antiepileptics	Neuropathic pain (e.g., gabapentin, pregabalin).	Use caution in renal failure.	Gabapentin 300–600 mg TID (max 3,600 mg/day); Pregabalin 75–150 mg BID (max 600 mg/day).
Antidepressants	Neuropathic pain, mood disorders (e.g., TCAs, SNRIs).	Caution in older adults or cardiac disease (QT prolongation).	Amitriptyline 10–150 mg daily; Duloxetine 30–60 mg daily.
Corticosteroids	Severe pain (capsular stretch, bone pain, raised ICP).	NSAID co-use (GI bleeding).	Dexamethasone 4–10 mg daily; Prednisone 10–40 mg daily.

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