Sodium bisulfite dosing

It has been suggested that sodium bisulfite, a preservative in phenylephrine solutions for injection, may have been responsible for transient neurological symptoms that have been observed in some patients (7). However, the original authors rejected this, since the dose of bisulfite was small and since there is uncertain evidence whether the compound is neurotoxic in any case. Another correspondent commented that tetracaine itself may be more toxic than other local anesthetics the authors did not address this point in their reply (8). 

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