RxCalc has slowly, but steadily gained functionality mainly due to some great user feedback we’ve received since it was initially released in July 2009.

So, what’s new in the latest release? Glad you asked. The featured changes include:

1. Support for dosing adjustment using single level vancomycin kinetics.
   • The calculations are performed using both patient specific information supplied by the user as well as patient population parameters.
2. Literature supported High Dose Extended Interval (HDEI) (aka “once daily” or “pulse”) aminoglycoside dosing.
   • Calculations for gentamicin and tobramycin are based on 7mg/kg adjusted body weight.
   • Calculations for amikacin are based on 15mg/kg adjusted body weight.

I have five free download codes for RxCalc. If you’d like to download the app for free just shoot me a quick email and I will send you one of the codes. It only takes a second and I’m sure you’ll like performing pharmacokinetics on your iPhone or iPod Touch. I know I do.

The codes expire in four weeks so make sure you contact me sooner rather than later.

Vancomycin and aminoglycoside (especially vancomycin) pharmacokinetics are very popular in hospitals, and are part of a select group of drugs that physicians prefer pharmacists to handle. Doing pharmacokinetic consults isn’t difficult per se, but can involve lots of numbers and equations. Many people find it a bit tedious and boring. There is also considerable variability in methods used for performing pharmacokinetic calculations. For example there are several existing pharmacokinetic models for vancomycin including Bauer, Matzke, Winter, Moellering, etc. Some of the models are more popular than others, but each has merit. As I’ve heard many times, “there are many roads to Rome.”

Pharmacists typically choose a favorite pharmacokinetic model and then alter the model to fit their needs based on years of clinical experience. I’m no different. Even though I was taught pharmacokinetics by Mike Winter at the UCSF School of Pharmacy, I prefer the vancomycin formulas derived by someone else. Please don’t tell Mike, he’s considered one of the best in the business and might revoke my alumni card if he found out.

Not all pharmacokinetic “starts” and adjustments require advanced calculations. Often times, years of experience and a good eye are all you need. However, there are times when you need a little more. Since the days of the Palm Pilot, I’ve always desired a portable pharmacokinetics program. It always made sense to me to use the technology at my finger tips to make my job easier. I’ve written several pharmacokinetic calculators, including simple Microsoft Excel spreadsheets and a little Java Script tied to a web front end, but I never got the opportunity to create a portable version. The iPhone (and iPod Touch) changed all that. The iPhone is a compelling device with a great user interface and unheard of popularity among healthcare professionals. My desire for a portable pharmacokinetics calculator, and the appearance of the iPhone, resulted in the creation of RxCalc.

RxCalc is designed for pharmacists based on my experiences over the past ten years. While not perfect, RxCalc does what I need. It’s clearly a work in progress. I don’t use it all the time because it’s simply not necessary. I still do a lot of “guess work” here and there, but rely on RxCalc when I need something to handle the more advanced calculations. Like every piece of software ever used, there is room for improvement. I have received lots of good, constructive feedback from several users. Combined with my desires, the feedback has created quite a list of future “enhancements” I’d like to see in RxCalc over the next several months. Among these include High Dose Extended Interval (a.k.a. once-daily) aminoglycoside dosing, single dose vancomycin kinetics, the option to change units (i.e. lbs, kg, cm, inches, etc), the ability to select different dosing models, alternate color schemes or themes and a more user friendly interface. Unfortunately, I don’t have the skill set to make the changes myself. That’s why God gave me a brother. I come up with the ideas and he does all the work to make it a reality. We make a great team.

I mentioned in a previous post that it may be time for me to put away my calculator in favor of newer technology. Pharmacokinetics was the last thing I really needed my calculator for. Well, with the creation of RxCalc I’ve finally put my calculator in the drawer and have been using pen, paper and my iPod Touch almost exclusively for a few weeks now. I must say, so far the results have been encouraging.

- Check out the LED Illuminated Message Board at Chinavasion Electronics. Imagine your typically white board on steroids. Use special pens to write on the dry erase surface without the backlight and you see nothing special, but flip the switch and you get fireworks. I frequently use a white board at work to sketch out ideas. I think this is a must have, and for under twenty bucks, it’s a bargain.

- Healthcare IT Consultant: “Can Pen And Paper Help Make Electronic Medical Records Better? – ScienceDaily (July 20, 2009) — The results of a new study of the pen and paper workarounds employed by healthcare providers who use an electronic medical record system may help make electronic medical records even more useful to health-care providers and the patients they serve….The most frequently cited reasons for using paper workarounds were efficiency and ease of use. Second most frequently was as a memory aid. The third most frequent reason was to recognize or alert others to new or important information.” – It’s all about changing the culture we practice in, and believe me I’m in the same boat as every one else.

- How about the “50 must-follow @Health20 heroes on Twitter“? It’s a pretty impressive list. You’ll certainly keep yourself busy trying to read all those ‘Tweets’.

- The Infectious Diseases Society of America, the American Society of Health-System Pharmacists, and the Society of Infectious Diseases Pharmacists have issued therapeutic guidelines for monitoring of vancomycin treatment for Staphylococcus aureus infection. The summary of consensus recommendations is published in the August 1 issue of Clinical Infectious Disease.  There’s nothing earth-shattering in the guidelines, but at least it’s all in one location now. The guidelines are available for free in PDF format here.

- The President is going to visit the Cleveland Clinic in hopes of finding the magic bullet for health care reform. Good luck.

- Apple continues to make other phone manufacturers unhappy as users drop their phones in favor of the iPhone. On the flip side, people continue to pound AT&T for terrible service and multiple problems. Wake up Apple, it’s time to open the iPhone up to other service providers.

- Engadget: “Looks like Hitachi has made some serious headway on the biometric payment system we first heard about way back in the halcyon days of 2007. According to the Mainichi Daily News, the company is currently testing its Finger Vein Authentication System internally, with the device serving as a method of payment for vending machines and the like. Once it’s proven that employees are able to get their Koala’s March and Hi-Chew without incident, the plan is to up the ante, with high precision ID systems that combine finger vein and finger print authentication systems for military use.” – Hey, how about a little love for pharmacy tech. We could use a high precision ID system like this for our automated dispensing cabinets.

- I found a new medical search engine built on data collected from other medical RSS feeds, it’s called Medworm and I like it.

- Amazon’s Jeff Bezos issued an apology over the removal of illegally sold copies of the book 1984 downloaded onto several Kindles. Bezos exact quote: “This is an apology for the way we previously handled illegally sold copies of 1984 and other novels on Kindle. Our “solution” to the problem was stupid, thoughtless, and painfully out of line with our principles. It is wholly self-inflicted, and we deserve the criticism we’ve received. We will use the scar tissue from this painful mistake to help make better decisions going forward, ones that match our mission.” – Ouch!

- There’s a new Wiki describing remote dispensing. Remote dispensing is a growing area in long term care and prisons. Companies like Talyst are developing new technology to promote this relatively untapped arena. I think acute care pharmacy could make use of some of this new technology;it’s just a matter of working out the kinks.

- Some of the funniest videos I’ve ever seen can be found on YouTube by searching for “Hitler gets banned from Xbox live“. The videos use some harsh language, but are laugh-out-loud funny.

RxCalc is an idea that my brother and I have had for quite some time. The idea for a portable pharmacokinetics calculator originated many years ago during my infatuation with the TRGpro and the Palm Operating  System. The timing for the application was never quite right, but the appearance of the iPhone changed all that. The portability, advanced features and popularity of the iPhone make it the ideal platform for developing a portable pharmacokinetics calculator.

RxCalc was designed as a tool for pharmacists to perform aminoglycoside and vancomycin kinetics, including new starts using population parameters and dosage adjustments using levels.

The code and user interface was written and developed by Apple Core Labs (Robert Fahrni), while I was responsible for the math and user experience (i.e. the workflow).

Apple Core Labs would like to recruit some pharmacists to use the application and provide feedback, good or bad. To receive a free promotional code redeemable at the iTunes store stop by the Apple Core Labs Blog and simply follow the instructions.