Datasheet link,
http://www.irf.com/product-info/datasheets/data/irlr3410pbf.pdfSwitching or linear?
SOA says you can go up to about 10V at 10A, so at least it won't explode suddenly!
More importantly, what's the thermal resistance in your end use? How much can you afford?
Examples: this is a DPAK, so you can mount it bare on the board (minimal pad), which I guess would be the 110 C/W figure they give. Which is 1.36W at 175C max Tj, 25C ambient, and much less for higher ambient.
Any means of spreading heat (big thermal pours, via-in-pad, heatsinking the board (top, bottom or both), solder-on heatsinks that straddle the device, etc.) will increase power dissipation, up to the thermal limit of the device itself (however, when they say Pd @ Tc = 25C, they mean
all points of the case simultaneously held at 25.0C with nucleated boiling liquid, so, you're unlikely to achieve the full 79W rating even in the best of circumstances).
At Rds(on) max 0.2 ohm (notice Rds(on) rises substantially with temperature; the 0.105 ohm figure is at Tj = 25C only), with a minimal footprint, you can do no more than 2.61A (DC or RMS). Which is around 3.69A in an average switching application (i.e., 50% duty cycle, say in a buck converter delivering that output current, with a generously large inductor so current ripple is small).
FWIW, you might as well use a SOT-89, -223 or SO-8 device if your current is that low -- you only waste space (and possibly money) with a DPAK. Even if your current is higher (which it is!), a smaller device may be more economical, because it's impractical to try getting lots of power from a DPAK.
Tim