What medication can be given for pain management?

Pain Management Medications

For pain management, start with acetaminophen (paracetamol) or NSAIDs for mild-to-moderate pain, escalating to opioids only for severe pain or when non-opioid therapies fail, following the WHO analgesic ladder approach. 1

Initial Assessment and Pain Classification

Before selecting medication, determine whether the pain is:

• Nociceptive (e.g., osteoarthritis, musculoskeletal pain): responds well to NSAIDs and acetaminophen 1
• Neuropathic (e.g., diabetic neuropathy, postherpetic neuralgia): requires different agents like gabapentinoids or antidepressants 1, 2
• Mixed or cancer-related: may require multimodal approach 1

WHO Analgesic Ladder Approach

Step 1: Mild Pain (Non-Opioid Analgesics)

Acetaminophen (Paracetamol):

• Dose: 500-1000 mg every 4-6 hours 1
• Maximum: 4000 mg daily 1
• Advantages: Superior safety profile, particularly in elderly patients; reduces opioid requirements when used in multimodal therapy 1
• Caution: Hepatotoxicity at excessive doses 1

NSAIDs:

• Ibuprofen: 400 mg every 4-6 hours as needed, maximum 3200 mg daily 3
• For localized osteoarthritis: Topical NSAIDs (e.g., diclofenac gel) preferred over oral NSAIDs in patients ≥75 years to minimize systemic effects 1
• Cautions: Use with gastroprotection for prolonged use; avoid or use cautiously in patients with hypertension, renal insufficiency, heart failure, peptic ulcer disease risk, or cardiovascular disease 1

Step 2: Moderate Pain (Weak Opioids + Non-Opioids)

Combination therapy:

• Acetaminophen or NSAID PLUS codeine (up to 240 mg daily), tramadol, or low-dose strong opioids 1
• Tramadol: 50 mg once or twice daily initially, maximum 400 mg daily; has dual mechanism (weak μ-opioid agonist + serotonin/norepinephrine reuptake inhibition) 1, 2
• Controlled-release formulations of codeine, dihydrocodeine, or tramadol may improve convenience 1

Step 3: Severe Pain (Strong Opioids)

Morphine is the first-choice strong opioid:

• Route: Oral administration preferred 1
• Conversion: Oral to IV/subcutaneous ratio is 1:2 to 1:3 1
• Titration: Start with immediate-release morphine every 4 hours plus rescue doses (up to hourly) for breakthrough pain 1
• Alternatives: Hydromorphone, oxycodone (both available in immediate and controlled-release formulations) 1
• Transdermal fentanyl: Reserved for stable opioid requirements; best for patients unable to swallow, poor morphine tolerance, or compliance issues 1

Critical opioid principles:

• Opioids should NOT be first-line for chronic non-cancer pain (>3 months duration) given small-to-moderate short-term benefits, uncertain long-term benefits, and serious harm potential 1
• Evidence is limited or insufficient for long-term opioid use in low back pain, headache, and fibromyalgia 1
• Mandatory co-prescription: Laxatives for constipation prophylaxis 1
• For nausea/vomiting: Metoclopramide or antidopaminergic agents 1

Neuropathic Pain Medications

When pain mechanism is neuropathic, standard analgesics are often insufficient:

First-line agents:

• Gabapentin: 100-300 mg at night initially, titrate to 900-3600 mg daily in 2-3 divided doses 1, 2
• Pregabalin: 50 mg three times daily or 75 mg twice daily initially, increase to 300 mg daily after 3-7 days, maximum 600 mg daily 2, 4
• Duloxetine (SNRI): 30 mg daily for 1 week, then 60 mg daily (can increase to 120 mg daily) 1, 2
• Tricyclic antidepressants: Nortriptyline or desipramine 10-25 mg nightly, increase to 50-150 mg nightly (secondary amines preferred over tertiary amines like amitriptyline due to fewer anticholinergic effects) 1, 2

Topical agents for localized neuropathic pain:

• Lidocaine 5% patch: Apply daily to painful site, minimal systemic absorption 1, 2
• Capsaicin 8% patch: Single 30-minute application provides relief for ≥12 weeks 2

Important neuropathic pain caveats:

• Allow at least 2-4 weeks at therapeutic dose before declaring treatment failure 2
• Combination therapy (gabapentinoid + antidepressant) provides superior relief compared to monotherapy 2
• Opioids are relatively less effective for neuropathic pain and should be reserved for refractory cases 1, 2

Multimodal Analgesia Strategy

Combining medications from different classes provides additive/synergistic effects while reducing individual drug doses and side effects: 1

• Acetaminophen + NSAID (or COX-2 inhibitor if no contraindications) 1
• Add gabapentinoid for neuropathic component 1
• Reserve opioids for breakthrough pain or when other modalities insufficient 1

Special Population Considerations

Elderly patients (≥75 years):

• Topical NSAIDs preferred over oral for localized pain 1
• Lower starting doses and slower titration for all medications 2
• Increased fall risk with sedating medications (tricyclics, anticonvulsants, opioids) 1

Renal impairment:

• Dose adjustment required for gabapentin and pregabalin 1, 2
• Fentanyl and buprenorphine are safest opioids in chronic kidney disease stages 4-5 (eGFR <30 mL/min) 1

Cardiac disease:

• Obtain screening ECG before starting tricyclic antidepressants in patients >40 years 2
• Limit TCA doses to <100 mg daily when possible 2

Common Pitfalls to Avoid

• Do not require patients to sequentially "fail" all non-opioid therapies before considering opioids—weigh expected benefits against risks in the specific clinical context 1
• Avoid prescribing opioids as scheduled medication for chronic non-cancer pain without exhausting other options 1
• Do not underdose acetaminophen—full 1000 mg doses are more effective than lower doses 1
• Do not combine tramadol with SNRIs/SSRIs without monitoring for serotonin syndrome 2
• Do not use NSAIDs long-term without gastroprotection 1