Physical and Chemical Compatibility of Extended-Release Triamcinolone Acetonide (TA-ER) with Common Local Anesthetics

Pharmacological and clinical implications of local anaesthetic mixtures: a narrative review

Various techniques have been explored to prolong the duration and improve the efficacy of local anaesthetic nerve blocks. Some of these involve mixing local anaesthetics or adding adjuncts. We did a literature review of studies published between 01 May 2011 and 01 May 2021 that studied specific combinations of local anaesthetics and adjuncts. The rationale behind mixing long- and short-acting local anaesthetics to hasten onset and extend duration is flawed on pharmacokinetic principles. Most local anaesthetic adjuncts are not licensed for use in this manner and the consequences of untested admixtures and adjuncts range from making the solution ineffective to potential harm. Pharmaceutical compatibility needs to be established before administration. The compatibility of drugs from the same class cannot be inferred and each admixture requires individual review. Precipitation on mixing (steroids, non-steroidal anti-inflammatory drugs) and subsequent embolisation can lead to serious adverse events, although these are rare. The additive itself or its preservative can have neurotoxic (adrenaline, midazolam) and/or chondrotoxic properties (non-steroidal anti-inflammatory drugs). The prolongation of block may occur at the expense of motor block quality (ketamine) or block onset (magnesium). Adverse effects for some adjuncts appear to be dose-dependent and recommendations concerning optimal dosing are lacking. An important confounding factor is whether studies used systemic administration of the adjunct as a control to accurately identify an additional benefit of perineural administration. The challenge of how best to prolong block duration while minimising adverse events remains a topic of interest with further research required.

Magnesium Sulfate Combined with a Levobupivacaine Periarticular Cocktail for Analgesia in the Early Postoperative Period after Total Knee Arthroplasty

This study aimed to evaluate the analgesic effect of magnesium sulfate combined with a levobupivacaine periarticular cocktail in the early postoperative period after total knee arthroplasty (TKA). A total of 60 patients who underwent primary unilateral TKA in our department from March 2018 to May 2019 were prospectively selected and randomly divided into the trial group (30 patients with 20 mL of magnesium sulfate 250 mg + levobupivacaine 50 mg + triamcinolone 25 mg + 0.9% normal saline) and the control group (30 patients with 20 mL of levobupivacaine 50 mg + triamcinolone 25 mg + 0.9% normal saline). Visual analog scale (VAS) scores at 6, 12, 24, 48, and 72 hours postoperatively during rest; VAS scores at 12, 24, 48, and 72 hours postoperatively during motion; the time required to reach 30 degrees straight leg elevation and 60 degrees active knee flexion; and the analgesia pump dosage at 6, 12, 24, and 48 hours postoperatively were recorded. Magnesium sulfate combined with levobupivacaine injection around the knee joint can significantly prolong the time of postoperative analgesia, significantly reduce the use of postoperative analgesics, and effectively alleviate early postoperative pain after TKA.

Triamcinolone Acetonide Extended-Release: A Review in Osteoarthritis Pain of the Knee

Triamcinolone acetonide extended-release (ER) 32 mg (Zilretta®) is approved in the USA for the management of osteoarthritis (OA) pain of the knee and is administered as a single, 5 mL intra-articular (IA) injection. Although the therapeutic effects from IA corticosteroids are typically short-lived, triamcinolone acetonide ER is formulated in poly (lactic-co-glycolic acid) (PLGA) microspheres that slowly release triamcinolone acetonide in the synovium, enabling their prolonged presence in the joint. This reduces systemic exposure and lessens corticosteroid-related systemic adverse reactions, such as blood glucose elevations. In a 24-week, randomized, phase III clinical trial, triamcinolone acetonide ER 32 mg significantly improved mean average daily pain intensity in patients with knee OA relative to placebo, and pain, stiffness and physical function (according to WOMAC criteria) relative to placebo and triamcinolone acetonide crystalline suspension (CS). Triamcinolone acetonide ER was generally well tolerated, with a tolerability profile similar to that of triamcinolone acetonide CS and placebo. Findings from a single-arm phase IIIb study indicated that a repeat administration of triamcinolone acetonide ER may be similarly efficacious to an initial injection without having deleterious effects on cartilage or other aspects of joint structure. Thus, triamcinolone acetonide ER expands the treatment options available for the management of OA pain of the knee.