Irritancy after intrathecal injection

Wallers K, Chaudhuri AKR, et al. Severe meningeal irritation after intrathecal injection of iopamidol. BMJ (Chn Res Ed) 1985 291 1688. 

The effects of intrathecal administration, both wanted and unwanted, are still much debated (448). The question as to whether oral glucocorticoid therapy should be preferred to intrathecal injections is raised by the harmful effects that have sometimes occurred after the latter, although some of these may have been caused by irritative substances in the injection fluid (SEDA-6, 331). The same local glucocorticoid concentrations can probably be attained with fewer problems with oral administration. Epidural injection of glucocorticoids seems to be safer than intrathecal injection, but injection of high doses can cause the same systemic adverse effects as seen with oral treatment. Facial flushing and erythema after lumbar... 

Since the canse of transient radicnlar irritation after hdocaine intrathecal anesthesia has not been elncidated, and although non-neurotoxic mechanisms mnst be considered, it has been recommended that the lowest effective doses and concentrations for intrathecal injection should be used (219). 

Parenteral products with osmotic values differing from the physiological value may cause phlebitis and irritation. This is especially applicable when the injection remains relatively long at the site of injection such as after subcutaneous, intramuscular, epidural and intrathecal administration. There is a higher chance of phlebitis in small vessels after intravenous administration. However, it is not known which limits should be considered to prevent phlebitis and irritation. According to some sources [22] the osmolarity of an intravenous injection should not be higher than 500 mOsm/kg. For subcutaneous and intramuscular administration the range is smaller. 

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