With recent innovations in pharmaceutical technology, important new methods of drug delivery have joined established ones. Prolonged-release oral preparations can provide precisely controlled drug delivery, which permits less frequent dosage of drugs with a short elimination half-life and thus improves compliance. These preparations also can narrow fluctuations in plasma levels, which maximizes efficacy and minimizes toxicity. Sustained-release intraocular and transcutaneous preparations offer similar advantages. Infusion pumps provide predictable systemic delivery of drugs that cannot be given orally or transcutaneously. Further innovations can undoubtedly be expected. When the therapeutic alternatives include a prolonged-release preparation, its potential advantages should be weighed against its potential disadvantages. Although some of these preparations cost more, this disadvantage may be outweighed by potential advantages.