What is the recommended ratio of lidocaine (local anesthetic) to Kenalog (triamcinolone) for a shoulder injection?

Recommended Lidocaine-Kenalog Mixture for Shoulder Injection

For shoulder injections, mix 4 mL of 0.5% lidocaine with 1 mL of triamcinolone (40 mg/mL) for a total volume of 5 mL, or alternatively use 10 mg lidocaine with 80 mg triamcinolone for larger volume injections.

Standard Mixing Ratios Based on Clinical Evidence

Lower Volume Approach (Steroid-Focused)

• 4 mL of 0.5% lidocaine + 1 mL triamcinolone 40 mg/mL 1
• This provides 20 mg lidocaine total with 40 mg triamcinolone
• Used successfully in ultrasound-guided intra-articular shoulder injections with demonstrated efficacy for pain relief and functional improvement 1

Higher Volume Approach (With Capsular Distension)

• 19 mL of 0.5% lidocaine + 1 mL ketorolac was used for capsular distension, suggesting larger volumes are safe 1
• For triamcinolone specifically: 10 mg lidocaine with 80 mg triamcinolone has been studied in acute rotator cuff shoulder pain 2
• This higher steroid dose (80 mg vs 40 mg) showed equivalent efficacy to other delivery methods 2

Critical Safety Considerations

Maximum Lidocaine Dosing

• Never exceed 4.5 mg/kg without epinephrine or 7.0 mg/kg with epinephrine 3
• For a 70 kg patient, this means maximum 315 mg without epinephrine or 490 mg with epinephrine 3
• The volumes recommended above (20 mg or even 95 mg lidocaine) are well below toxic thresholds 3

Avoid Concurrent Local Anesthetic Use

• Do not perform shoulder injection within 4 hours of any other local anesthetic intervention (nerve blocks, infiltration, etc.) 4
• This prevents cumulative local anesthetic toxicity from multiple sources 3, 5

Practical Application Algorithm

Step 1: Choose your approach based on clinical scenario

• For simple intra-articular injection without capsular distension: Use 4 mL lidocaine 0.5% + 1 mL triamcinolone 40 mg/mL 1
• For acute rotator cuff pain requiring higher steroid dose: Use lidocaine 10 mg + triamcinolone 80 mg 2

Step 2: Verify patient weight and calculate maximum safe dose

• Calculate: 4.5 mg/kg (without epinephrine) or 7.0 mg/kg (with epinephrine) 3
• Confirm your mixture stays well below this threshold

Step 3: Confirm no recent local anesthetic exposure

• Ask about any nerve blocks, dental procedures, or other local anesthetic use in past 4 hours 4

Step 4: Monitor for toxicity signs

• Early signs: tinnitus, metallic taste, circumoral numbness 3, 5
• Progressive signs: muscle twitching, slurred speech 3
• Severe signs: seizures, cardiovascular collapse 3

Common Pitfalls to Avoid

Pitfall 1: Using Excessive Lidocaine Concentration

• The evidence supports 0.5% lidocaine (5 mg/mL), not 1% or 2% concentrations for shoulder injections 1, 2
• Higher concentrations increase risk of toxicity without added benefit for this indication

Pitfall 2: Ignoring Cumulative Dosing

• Always account for total local anesthetic exposure from all sources 3, 5
• A seemingly safe shoulder injection can become toxic if patient recently had dental work with lidocaine or another regional block 4

Pitfall 3: Inadequate Anesthesia for Reduction

• For acute shoulder dislocation reduction specifically, 20 mL of 1% lidocaine intra-articularly has been validated as providing excellent anesthesia 6
• This is a different indication than therapeutic steroid injection and requires higher volume for adequate joint distension 6

Evidence Quality Notes

The mixing ratios are derived from prospective studies specifically examining shoulder injections 1, 2, making them directly applicable to your question. The 4 mL + 1 mL mixture has been validated in ultrasound-guided techniques with good safety profiles 1. The safety parameters come from high-quality consensus guidelines 4, 3 that should always be respected regardless of the specific mixture used.