Which injectable medications are used for pain relief and what are their associated risks?

Injectable Medications for Pain Relief: Evidence-Based Overview

Based on the most recent high-quality evidence, injectable pain medications show limited to no meaningful benefit for chronic spine pain, with potential for serious harms, and should be used with extreme caution or avoided in most cases 1.

Common Injectable Pain Medications

The most frequently used injectable agents for pain management include:

• Corticosteroids (epidural, joint-targeted, intramuscular)
• Local anesthetics (lidocaine, bupivacaine)
• Combination injections (steroids + local anesthetics)
• Hyaluronic acid (primarily for osteoarthritis)
• NSAIDs (ketorolac/Toradol)

Critical Evidence for Chronic Spine Pain

The 2025 BMJ guideline provides definitive evidence that should fundamentally change practice patterns 1:

Moderate Certainty Evidence (Unlikely to Change):

• Epidural injections of local anesthetic (with or without steroids) for chronic axial spine pain: NO meaningful pain relief
• Joint-targeted steroid injections for chronic axial spine pain: NO meaningful pain relief
• Epidural injections with steroids for chronic radicular spine pain: NO meaningful pain relief
• Dorsal root ganglion radiofrequency for chronic radicular spine pain: NO meaningful pain relief

All these interventions showed "little to no effect" compared to sham procedures 1.

Serious Safety Concerns

Between 1997 and 2014, the FDA Adverse Event Reporting System documented 90 serious adverse events occurring within minutes to 48 hours after epidural corticosteroid injections, including 1:

• Death
• Spinal cord infarction
• Paraplegia and quadriplegia
• Cortical blindness
• Stroke
• Seizures
• Brain edema

Additional Documented Risks:

• 8.6% risk of prolonged pain or stiffness (>48 hours)
• 2.1% risk of temporary altered consciousness
• 1.4% risk of dural puncture
• 0.7% risk of deep infection
• Risk of meningitis from infection 1

Specific Injectable Agents and Their Risks

Corticosteroids

For osteoarthritis, corticosteroids provide only short-term benefit (up to 3 weeks) and carry risks of chondrotoxicity with repeated use 2, 3. The timing must be coordinated with potential surgical dates, as they can interfere with healing 2.

Local Anesthetics

Caution is essential due to chondrotoxicity concerns when used with corticosteroids 2. When using intravenous lidocaine for perioperative pain:

• Maximum dose: 1.5 mg/kg loading over 10 minutes, then 1.5 mg/kg/h infusion
• Use ideal body weight for dosing
• Do NOT use in patients <40 kg
• Maximum infusion rate: 120 mg/h regardless of weight
• Cannot be combined with regional blocks within 4 hours 4

Hyaluronic Acid

Routine use is NOT recommended 2. Consider only in patients who have failed other therapies, with modest benefit expected between 5-13 weeks post-injection 3. The placebo effect is substantial and must be acknowledged 3.

Injectable NSAIDs (Ketorolac/Toradol)

Provide significant analgesia through COX pathway inhibition 5. Major concern: bleeding risk, though not accurately quantified 5, 6.

Contraindications include:

• Asthma or aspirin/NSAID allergy
• Peptic ulcer disease
• Bleeding disorders
• Elderly patients require extra caution 6

Clinical Decision Algorithm

For Chronic Spine Pain (Axial or Radicular):

1. Do NOT offer epidural steroid injections, joint injections, or nerve ablation procedures as routine treatment - they provide no meaningful benefit over sham 1
2. If a patient insists despite counseling, ensure informed consent includes the serious adverse events listed above
3. Recognize that any perceived benefit is likely placebo effect (saline injections show similar improvements) 2

For Osteoarthritis:

1. First-line: Non-injection therapies (weight loss, physical therapy, oral medications)
2. If injection considered: Single corticosteroid injection for short-term relief (≤3 weeks) in carefully selected patients 2, 3
3. Avoid repeated corticosteroid injections due to chondrotoxicity 2
4. Do NOT routinely use hyaluronic acid - reserve for failed conventional therapy only 2

For Acute Postoperative/Trauma Pain:

1. Injectable NSAIDs (ketorolac) are reasonable when opioid-sparing analgesia is desired 5, 6
2. Screen for contraindications (bleeding disorders, peptic ulcer, renal disease, elderly)
3. IV lidocaine infusions can be used perioperatively with strict dosing protocols and monitoring 4

Critical Pitfalls to Avoid

1. Do not assume "standard practice" equals evidence-based practice - epidural steroid injections are extremely common despite lack of efficacy 1
2. Do not combine local anesthetic modalities - IV lidocaine cannot be given within 4 hours of regional blocks 4
3. Do not inject local anesthetics directly into tendons - increased rupture risk 5
4. Do not overlook the substantial placebo effect - intra-articular saline shows similar improvements to active treatments 2
5. Do not repeat corticosteroid injections frequently - chondrotoxicity accumulates 2

The burden of proof has shifted: given moderate certainty evidence of no benefit and documented catastrophic harms, the default position should be to avoid these interventions for chronic spine pain unless compelling individual circumstances exist 1.