Technology in Practice 

Using Personal Digital Assistants In Clinical Pharmacy Practice: Commonly Asked Questions

Robert M. Balen, B.Sc.(Pharm), Pharm.D.1 , Peter S. Loewen, B.Sc.(Pharm), Pharm.D.2 
1Associate Editor, 2 Publishing Editor Journal of Informed Pharmacotherapy, 
J Inform Pharmacother 2003;13:500.

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Unless you have been practicing in isolation, detached from the modern world, you will have heard of them. They are becoming almost as common as the pager and may have already infiltrated your healthcare team, your department and maybe even your family. You may even have experienced the bewildered stare of a colleague when they exclaim, "You mean… you don't have one?" We are, of course, referring to the Personal Digital Assistant (PDA). Point of need access to your schedule, phone numbers and tertiary clinical resources has never been more rapid. Clinical resources and data management are being revolutionized by PDAs and to ignore their capabilities may be hazardous to the advancement of your practice.

PDAs are small hand-held computers. They allow users to input and retrieve data and can provide a rapid and effective means of accessing, retrieving, analyzing, sharing and storing large volumes of practice-related information wherever it is needed.

The authors have over a decade of cumulative experience using PDAs based on the Palm Operating System for personal and practice related data management in internal medicine and critical care pharmacy practice specialties. Unfortunately, many clinicians still feel mystified by these devices or uncertain as to how they might help to improve their effectiveness in their day-to-day practice. In this article we address some commonly asked questions about PDAs we've received from our students, colleagues, and new and experienced PDA users from numerous healthcare disciplines. It is not our aim to convince you of the need for a PDA (your colleagues can provide the demonstrations of that) but rather to demystify many of the technical issues that arise while selecting and using a PDA.


I hear that you are quite the PDA experts, is that true?

That depends on your definition of "expert". We have participated in numerous PDA related presentations for pharmacy and allied disciplines and have presented posters and delivered podium presentations on PDA use in pharmacy practice at numerous professional conferences. In addition, we have some experience in developing custom applications for clinical practice.(1-7) If knowing just a little bit more than the person asking the question qualifies us as experts, relatively speaking, we'll play along.

Are your recommendations evidence-based or CRAP?

We are CRAP-based.(8) At least we honour our computerised evidence-based decision support software.

Do I really need to get a PDA?

Acquiring a PDA for the purposes of improving your clinical practice effectiveness may not be necessary for everybody. However, an awareness of what the current state of this technology is and how it is being integrated into clinical practice may cause you to join the ranks of those who are using PDAs. Also, you may be interested to know how other disciplines are using PDAs to meet their own needs, since this is likely to influence the sorts of demands for knowledge they have of you.

What PDA should I buy?

Once you start shopping for a PDA the number of models available may overwhelm you. Fortunately, many of the devices on the market today can be categorized according to a small number of key distinguishing features. Once you have determined what key features you want, the selection of a device is quite straightforward.

Key Feature #1: The Operating System (OS)

The operating system is the engine of the PDA. Currently consumers have a choice of two major operating systems. These are the Palm OS and the Windows-based Pocket PC. Each has its strengths and recent advances in both of these systems are blurring their former lines of distinction. Detailed feature-by-feature differences between the Palm and Pocket PC OS are readily available. (9-11)

Our experience lies largely with Palm OS devices and to date these have met all of our practice-related information management needs. We initially started using Palm OS devices because they were less expensive, smaller, faster, had more widely available healthcare-related software applications. Although the Pocket PC has narrowed the gap in many of these categories we still recommend Palm OS devices to our colleagues and the remainder of this article will focus on this operating system.

Key Feature #2: Random Access Memory (RAM)

RAM is the type of memory or storage room, measured in mega-bytes (MB), that the PDA uses to run programs. It is essential to have enough RAM to run all your software. Each application will require a certain amount of memory and  similar PDAs may provide differing amounts of RAM. Users should be aware of how much RAM is available on the PDA that they are considering purchasing. Typically Palm OS based devices offer 2 MB, 8 MB or 16 MB of RAM. Memory can be expanded on most newer PDAs with the use of external memory media (Memory Stick® for Sony® branded devices and Secure Digital® cards for Palm® branded devices). Setting up programs to function off of external media cards adds a few extra steps to the installation process and not all software applications are fully functional when working off memory cards…yet.

The "appropriate" RAM requirements will vary between individuals depending on the mix of applications that are chosen. For example a "core" bundle of clinical resource software such as a drug information database, a drug interaction analyzer, and a disease based reference database can occupy 10 MB of RAM or more. In order to use all of these applications without resorting to external memory cards, a PDA with 16 MB of internal RAM is required (the next lowest increment is 8 MB). Insufficient RAM will limit how many programs or how much data can be stored on the PDA. While expanding memory with external memory media is an option, trying to run memory-hungry programs from external memory media is perhaps the most frequent cause of frustration among new PDA users.

Key Feature #3: The Screen

Screen resolution refers to the clarity and detail with which text and images appear on the PDA screen. Screens are are usually classified as high or low resolution. High-resolution screens provide at least a 320 X 320 pixel display as compared to the 160x160 pixel display of the low resolution screens. Higher resolution output provides a sharper image and allows some devices (e.g. Sony) to display smaller fonts which permit much more content to be viewed on the screen. (Figure 1)

PDA screens are also differentiated by color capability. Monochrome screens are capable of displaying black white and a few shades of gray, while color screens can display around 65,000 colors or more. Monochrome devices are less expensive and are adequate for viewing most text-based sources of information typically used in clinical practice. Color may provide a more pleasing presentation of information but will typically add at least $100.00 to the cost of a PDA.

Color screens also put heavier demands on the battery life of the PDA than monochrome displays. Almost all color PDAs (except possibly the Sony Clie® NR and NX models) will stand up to a full day of intermittent use. However, if you are not able to recharge at least every two days, steer clear of a color PDA. On the other hand, monochrome PDAs generally sustain a week of intermittent use between charges.

Keep in mind that some color screens ("backlit screens") are not viewable under bright sunlight. Others ("frontlit" or "transflective" screens) become clearer as the ambient light increases. In clinical practice, frontlit screens are preferred, unless your practice setting is outside. If it is, please send us an application form.

Figure 1. High vs. low-resolution screen displays of identical content. More columns are visible in a high resolution, small font view. More vertical and horizontal scrolling is required to view right-sided columns in low-resolution view. Small fonts are not viewable on low-resolution screens.

A) High resolution 320 X 320 pixels with small fonts. B) Low resolution 160 X 160 pixels

Enough technical stuff already, which PDA should I buy?

This is one of the most common questions that we get from colleagues entering the PDA arena. The answer we give changes from time to time depending on our mood and the new hardware releases and features deemed to be important to the user. Our philosophy of choosing a PDA is as follows: Look for the least expensive Palm OS based device that offers the features you require.

For clinical pharmacy practice we recommend a high-resolution monochrome screen and 16MB of internal RAM with expandable memory capability. For example, the Sony Clie® SJ20 or SJ22 fits the bill nicely at CDN$225 or $300. If color is important and there is an extra $150.00 in the budget, step up to a color device (eg. Sony Clie® SJ33, Palm Zire® 71). Users who desire voice recording, music file play back and built-in wireless internet or corporate network access capability will be satisfied with higher-priced models such as the Sony Clie® SJ33 or TG50 or Palm Tungsten T® or Tungsten C®. At present these features, in our opinion, add "fun factor" and possibly longevity to the device, but are of limited benefit toward improving clinical pharmacy practice effectiveness. For some, voice recording may be useful for clinical note-taking, although we have not integrated this into our practices as yet. In future, as healthcare institutions enable wireless PDA based access to corporate network, library and other patient care resources, incorporating the wireless capability into the PDA purchasing decision could become more important. We suspect that for most, this will not happen before another generation or two of PDAs are developed, and we suggest you not invest in a handheld with wireless networking unless you have an immediate need for it.

What clinical resource software should I get?

Despite the potential for wireless access to information and the ability to manage practice related data, we believe that the single most valuable aspect of integrating a PDA into clinical practice is the ability to make a large volume of personalized clinical resources available at the point of need. To this end, numerous software options are available. A recent publication has catalogued much of the software currently available for healthcare practitioners. (12) Many of these programs can be used for free on a trial basis. Some examples are included in Table 1. Before purchasing any software, users should experiment with a wide variety of resources to determine their utility in specific practice environments. Resources devoted to the three major domains; drug information, drug interaction analysis, and disease information can arm you with much of the point of care information that you need for most practice settings. 

Resources for specialty practice settings such as pediatrics, cardiology, critical care, infectious diseases and others, are also available. Few reports that objectively compare the usefulness of these resources in the clinical arena are available. In our experience, Lexi-Drugs PlatinumTM  provides the most comprehensive tertiary drug information available. A recent report by Enders et al supports this anecdotal impression. (13) iFactsTM  and Lexi-InteractTM  provide thorough and fully referenced drug interaction analysis while ePoctrates RXTM is excellent for a quick screen of drug interactions, but has few supporting details. The Griffith's 5-Minute Clinical ConsultTM  provides good disease-based information that would be useful in a broad range of clinical practice settings.

Table 1. Examples of Drug Information, Drug Interaction Analyzers, and Disease-Based Palm OS PDA resources

Software/ Publisher

Vendor Website

Cost*  (USD)


Drug Information Software

Lexi-Drugs™ Platinum/

Lexi-Comp, Inc.


Over 1600 drug monographs

Includes Canadian drugs/brands and off-label indications

Very comprehensive monograph information

Memory requirement 4-6MB depending on installation options

MosbyRx™ /

Mosby, Inc.



Approx 1000 drug monographs

Memory requirement 2.4 MB

A2zDrugs™ /

Facts & Comparisons


Approx 700 drug monographs

Memory requirement 3.1 MB

ePocrates Rx™ /

ePocrates, Inc.


Approx 2700 drug monographs

Multi drug interaction checker feature

Very brief monographs

Memory requirement 2.5 MB

Drug Interaction Software 


(Drug Interaction Facts)/

Facts & Comparisons


Detailed information organized into 8 categories

Identifies precipitating drug

References included

Memory requirement 3 MB


Lexi-Comp, Inc/


Comprehensive and similar in scope to iFactsTM

Rating scale for interaction significance

Memory requirement 3.1 MB

ePocrates Rx™/

ePocrates, Inc.

Free **

Brief information

Drug interaction check feature is included as part of the drug information database

Memory requirement 2.5 MB including drug information data

Disease Information Software

Griffith's: 5 Minute Clinical Consult /

Lippincott William & Wilkins OR


Memory requirement 4 – 7.6 MB depending on vendor and installation options

* Costs as of February 2003  ** Subscriber usage data is collected

What "other" software is useful for clinical practice?

There are numerous other valuable resources for healthcare providers. These include document converters and readers that allow you to create your own resource content by converting various document formats from desktop PC to PDA compatible format (eg. Documents-to-Go®, Wordsmith®), calculators for common clinical formula calculations (eg. MedCalc®, MedMath®), calculators for evidence based medicine and statistical calculation (eg. EBMcalc), scheduling tools, database development software (eg. HanDBase®) and others. A full description and practice integration examples of some of these additional applications will be the subject of upcoming Technology In Practice Section (TIPS) articles.

Why is it that some of my programs won't work off my memory card?

The PDA communicates with the memory card using something called a virtual file system (VFS). Some software applications are VFS compatible and can be installed to external memory media while some software applications will only work on internal RAM. There are some third party software applications available that will facilitate communication between the PDA and external memory media, or move applications temporarily to and from internal RAM and external memory media.  These applications can be used to make some non-VFS compatible software run off memory cards and some examples include PiDirect II ( ), PowerRun ( ) and MSMount (available from . Detailed descriptions of how these utilities work are beyond the scope of this article. Operating non-VFS compliant software using one of these utilities adds a level of complexity that can be frustrating for the novice PDA user. Fortunately most core clinical resource software is now fully VFS compliant and can be installed directly on to external memory media.

Is it possible to print from the PDA?

Yes it is, although additional software is needed to send the printing instructions from the infrared port on the PDA to a printer that is capable of receiving an infrared signal. Examples of applications that enable printing from the PDA are PalmPrint® ( and PrintBoy® ( ). To date we have found few practical reasons to print from a PDA.

Are there any good programs available for patient tracking?

There are several commercially available programs designed for patient tracking. These include Epatient ( ), Patient Tracker ( ) and PatientKeeper ( ). These software applications resemble mini electronic charts with numerous fields for patient care related data entry. We do not currently use any of these patient-tracking programs for several reasons. First, we do not have a full systems interface for PDAs within our healthcare organizations and populating many of the fields on these programs would require manual entry of data. Second, these programs appear to be structured in accordance to a physicians approach to patient care i.e. diagnosis of medical problems. As clinical pharmacists we focus on solving and preventing drug related problems rather than performing medical diagnoses and these tracking programs don't focus on this approach to patient care. Third, currently available database development software can be used to create patient consult management databases that are more targeted to our pharmaceutical care approach, resulting in data that is more amenable to sharing and analysis.


PDAs are small hand-held computers that enable users to input and retrieve data and thus can provide an effective means of accessing, retrieving, analyzing, sharing and storing large volumes of practice-related information at the point of need. Clinicians should be aware of the current state of this technology and how it can be used for improving practice. Comprehensive tertiary drug and disease references are currently available in PDA format. Pharmacists interested in integrating a low cost PDA into their practice should consider choosing a Palm OS device with a monochrome high-resolution screen and 16 MB of internal memory capacity to run software applications. External memory cards can expand the memory capacity of most PDAs, but not all applications are fully functional when running off of these storage media. A core clinical resource software package includes comprehensive references providing information from both drug and disease based perspectives. So, consider the benefits of integrating a PDA into your own practice. Based upon our experience, you won't be disappointed. 

Authors Competing Interests

The authors have not received any research funding, speaker honoraria, complimentary hardware or software from any company for any product pertaining to this manuscript.


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