In the Compact Linear Collider (CLIC) now being studied at CERN, the rf power which accelerates the main beam is provided by decelerating a high current drive beam. The drive-beam linac has to accelerate a 4.2 A electron beam up to 2.4 GeV in almost fully loaded structures. The pulse contains about 70 000 bunches, one in every second rf bucket, and has a length of 140μs. The beam stability along the beam line is of concern for such a high current and pulse length. We present different options for the lattice of the linac based on FODO, triplet, and doublet cells and compare the transverse instability for each lattice including the effects of beam jitter, alignment, and beam-based correction.