In the management of snake bite after first aid what antivenom can be used generally in most cases, dose and route?

First Aid for Bite: A person bitten by a poisonous snake must go to an emergency room for treatment beyond basic first aid (easily reviewed on sites like webmd or medlineplus) the administration of Antivenin or other injectibles (except Epinephrine if person is prescribed one) should be done by trained professionals. You will likely do more harm than good! fatality in us for bites is 0.2% less than bees and wasps!

It depends: Antivenom used in snakebite depends on where you are, and the type of snake that has bitten you. Also it depends on the extent of symptoms you have -- receiving antivenom is not risk-free, and the er doctors have to assess risk vs benefit in each case. In the us there's an antivenom for rattlesnakes, copperheads, and water moccasins. It's given iv, in consultation with a toxicologist.