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Psyber Psychiatry, Commentary

PDA prescription program pros and cons

Some drug reference products are more accurate, others more comprehensive.

Vol. 5, No. 9 / November 2006

Personal digital assistant (PDA)-based drug reference software can help you make informed point-of-care prescription decisions, but accuracy, usability, and comprehensiveness vary greatly among programs.

This article looks at the benefits and drawbacks of popular PDA drug reference programs and offers advice on choosing the right one for your practice.

PDA Program benefits

Equipping your PDA with drug reference software makes prescription information portable and accessible. PDA-based drug guides also:

  • are easy to update. Most PDA-based systems automatically update as part of routine synchronization procedures between the device and its host computer, keeping the information up-to-date. This is an important feature as some drug databases are updated daily.
  • list potential side effects. Most programs list all potential medication side effects and distinguish between common and uncommon adverse events.
  • list possible drug-drug interactions. This feature gives PDA-based drug guides a clear advantage over print textbooks. Users enter two or more medications, and the program searches for potential interactions between them.
  • list interactions with alternative medications. Many databases include herbal supplements and other nontraditional pharmaceuticals.
  • offer additional tools, such as medical calculators, treatment algorithms, and other handy features.


Because PDA screens are so small, PDA-based drug guides must compromise between level of detail and ease of use. Unlike standard drug reference books, for example, PDA programs rarely list rates of side effects or comparisons with placebo.

PDA-based drug guides usually do not display references or analyses of the data behind the lists. For example, many programs provide dosing suggestions for special populations—such as the elderly, medically ill, and children—but the basis for these dose adjustments often is unclear or does not jibe with other programs. Most PDA drug software excludes other specific information, such as the evidence behind drug indications.

Researchers’ ratings

Some PDA-based drug databases, such as mobilePDR, evolved from written pharmacy databases. Others, such as ePharmacopoeia or Epocrates, were developed from more-general reference tools aimed at students and physicians. Overall, the former type of drug guide is more comprehensive and the latter is easier to use, although all PDA drug software offers some degree of comprehensiveness and usability.

PDA-based programs differ greatly, however, and the following researchers have explored the differences.

  • Enders et al1 in 2001 rated Lexi-Drugs Platinum the most comprehensive and accurate among nine programs.
  • Galt and colleagues,2 placing more weight on safety concerns than ease of use, in 2005 also rated Lexi-Drugs Platinum number one among 11 programs.
  • Clauson et al3 in 2004 rated Lexi-Drugs number one among 10 programs, but noted that other products were catching up.
  • Knollmann et al4 in 2004 rated 11 PDA-based drug databases on ease of use, comprehensiveness, and accuracy. They entered three pairs of drug names into each program; one pair included an herbal supplement.
  • Perkins et al5 in 2004 entered 37 pairs of drug names into eight programs to test their ability to detect drug-drug interactions. They found that Epocrates offered the best combination of sensitivity (identifying all potential interactions) and specificity (reporting only important interactions). Lexi-Drugs had perfect sensitivity but comparatively poor specificity.

Which program should you choose?

No PDA-based drug reference will provide everything you need, so be clear on what you desire most when choosing a program:

  • If drug safety is your primary concern, Lexi-Drugs might be best, although it tends to report clinically insignificant interactions.
  • If you want only clinically significant interactions, consider Epocrates or Epocrates RX Pro.
  • If a comprehensive database is critical, Clinical Pharmacology OnHand has the most extensive drug database.
  • If you’re looking for the best combination of accuracy, comprehensiveness, and physician-friendly features, Lexi-Drugs and PEPID PDC might be most effective, though Epocrates is also a reasonable performer.
  • If you wish to understand the evidence behind each recommendation, books and online pharmaceutical references remain better options.

Cost is another factor. This might explain why Epocrates—which offers a free version for physicians and medical students—is more popular than Lexi-Drugs, which is one of the most expensive programs at $70 for the basic version and $285 for the comprehensive suite. Most programs have two options: a less expensive—or even free—drug database that costs up to $75 and a suite of features such as treatment algorithms or diagnosis databases that range from $60 to almost $300.

Personal experience is the best way to determine which product is best. Most manufacturers let you try their programs before buying.

Related resources

Chan CH, Luo JS, Kennedy RS. Concise Guide to Computers in Clinical Psychiatry. Washington DC: American Psychiatric Press; 2002

American Association for Technology in Psychiatry.

1. Enders SJ, Enders JM, Holstad SG. Drug-information software for Palm operating system personal digital assistants: breadth, clinical dependability, and ease of use. Pharmacotherapy 2002;22:1036-40.

2. Galt KA, Rule AM, Houghton B, et al. Personal digital assistant-based drug information sources: potential to improve medication safety. J Med Librar Assoc. 2005;93:229-36.

3. Clauson KA, Seamon MJ, Clauson AS, et al. Evaluation of drug information databases for personal digital assistants. Am J Health Syst Pharm 2004;61:1015-24.

4. Knollmann BC, Smyth BJ, Garnett CE, et al. Personal digital assistant-based drug reference software as tools to improve rational prescribing: benchmark criteria and performance. Clin Pharmacol Ther 2005;78:7-18.

5. Perkins NA, Murphy JE, Malone DC, Armstrong EP. Performance of drug-drug interaction software for personal digital assistants. Ann Pharmacother 2006;40:850-5.

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