DISCLAIMER: I'm providing the following excerpt for INFORMATION ONLY, not at a TREATMENT guideline!! Edited slightly for length.

From Harrison's Principles of Internal Medicine, 16th Ed., P. 2593:

"Initial (prehospital) measures should focus on rapidly delivering the victim to definitive medical care while keeping him/her as inactive as possible to limit systemic spread of venom. Any other measures employed should at least do no further harm to the victim.
Although mechanical suction has been recommended in the field management of venomous snakebite for many years, there is now literature that demonstrates that this intervention is of little, if any, benefit...
...There is concern that severely restricting venom to the bite site may, in fact worsen local tissue necrosis. If the victim is >1 hour from medical care, a constriction band or pressure-immobilization may be considered, but with realization that one may be sacrificing tissue in order to reduce systemic toxicity... The bitten extremity should be splinted if possible and kept at approximately heart level.
For elapid or sea snake bites, the Australian pressure-immobilization technique, in which the entire bitten extremity is wrapped with an elastic or crepe bandage and then splinted, is highly effective..."

There are several more pages of in-hospital treatments, but that's outside this discussion (and quite frankly, my expertise and experience).