Aggregation properties of triamcinolone acetonide injection in human serum: considerations when performing epidural steroid injections

Delineating injectable triamcinolone-induced cutaneous atrophy and therapeutic options in 24 patients—A retrospective study

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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.

Vision Loss Secondary to Facial and Periorbital Steroid Injection: A Systematic Review

PURPOSE

The risk of ophthalmic and retinal artery occlusions following facial and periorbital steroid injection has not been explored. This systematic review examines the prevalence, risk factors, and treatment outcomes of steroid-induced vision losses.

METHODS

A literature search in Evidence Based Medicine Reviews, MEDLINE, Embase, Pubmed, ClinicalTrials, and WHO ICTRP was performed for vision loss following facial and periorbital corticosteroid injections through July 2020.

RESULTS

Of 35 case reports, series, and reviews, 49 patients (56 eyes) with steroid-induced vision loss were analyzed. Injection sites predominantly involved the nose (45%) and periocular regions (10%). The most common type of steroid is triamcinolone (54%). Most cases were unilateral, except 7 cases of bilateral vision losses, 4 of which resulted from unilateral steroid injection. Symptoms were reported during or immediately after injections in 49% of cases. Most occlusions occurred in the ophthalmic (53%) or central retinal artery (33%). Vision most commonly presented as no light perception (37%), and 90% were 20/200 or worse. Final visual outcomes varied from 20/200 or worse (56%), 20/40 or better (30%), to in between (13%).

CONCLUSION

Most vision losses resulted from steroid injections in the nasal and periorbital area. Triamcinolone was the most common offending agent, likely due to large particle size, low solubility, and extensive particle aggregation. Dexamethasone has the opposite pharmacologic properties and has never been reported in association with vascular occlusion related vision loss. Careful steroid selection, injection techniques, and treatment strategies should be considered to prevent and treat artery occlusion.