A unit dosage form, such as a capsule or the like for delivering drugs into the body in a sustained release fashion similar to that produced by INDERAL® LA indicated for the treatment of cardiovascular diseases, comprises two populations of propranolol-containing particles (beads, pellets, granules, etc.). Each bead population exhibits a pre-designed rapid release profile (i.e., substantially complete release within 60 minutes) or sustained release profile over a period of 24 hours. Such a cardiovascular drug delivery system is designed by combining immediate release (IR) beads and sustained release (SR) beads. SR beads may be obtained by membrane coating IR beads with a water-insoluble polymer such as ethylcellulose or a mixture of a water insoluble polymer and a water-soluble polymer such as hydroxypropylcellulose at a ratio of from about 65/35 to 95/5.