A dosing regimen for formulations that contain a therapeutic dosage of a site 1 sodium channel blocker, where the dosing regimen provides a prolonged nerve block and is in an effective amount to delay the onset of neuropathic pain, such as hyperalgesia and/or allodynia, for at least one week, and preferably longer at the site, and preferably the region (e.g. entire limb), where the nerve block was applied. The site 1 sodium channel blocker is preferably saxitoxin (STX), preferably in combination with a corticosteroid, preferably dexamethasone. In a preferred embodiment, liposomes are included in the formulation as a controlled release system, producing prolonged duration of block without systemic toxicity. As demonstrated by the examples, encapsulating STX in a controlled release system, such as liposomes, preferably also including a corticosteroid, and administering in suitable dosing regimen to achieve a prolonged nerve block without systemic toxicity, delays the onset of hyperalgesia.