I don't know if a 99 Altima has any special problems, but many others are a PITA. Start with the parking brake off. Look for screws holding the drum on. They tend to fit tightly around the hub. Sand the rust of what sticks out back as close as you can. Give it a good squirt of penetrating oil around the hub and studs. Sometimes you can then wiggle it off. If not, it means a hammer or torch. Modern drums do not have excess metal. They break. Still you can hit it fairly hard between the studs where it is supported by the hub. Do not ask King Kong to help with that. Also work at knocking it sideways from the outer edge. Since this is unsupported, thin, cast iron, you want more of a tap than a pound. Usually it finally starts off when you are hitting it with one hand, and pulling with the other.
Often a torch makes quick work of the job, but uneven heat can distort the drum.
Sand all the rust off, and apply antisieze to the hub before putting it back on. I would put some oil or antisieze on the studs too, and reduce the tightening torque by 20%. Others, including the manufacturers, insist the lug nuts should be installed dry.