Antibiotic Kinetics© support FAQ's

FAQ

FAQ is an acronym for Frequently Asked Question. This page is intended to provide answers to common questions, along with some useful tips and tricks that are presented as questions.

General questions
Desktop FAQs
PDA questions
PalmOS FAQs
Windows Mobile FAQs
Android FAQs


General questions

Why are there two Vancomycin models in the program?

Vancomycin is a difficult drug to dose because of extreme inter-patient variability of pk parameters. No single model will fit all patient populations.

Patients who may be more appropriately dosed with the outlier model include:

Please bear in mind that vancomycin is not a very predictable drug, and these models will not fit all patient populations. It is important to save your data, and to periodically re-analyze your population parameters vs outcome.

How do I adjust a dose based only on a trough level?

You may analyze a single trough, a single peak, or a random level drawn at any point within the dosing interval by selecting the single point Bayesian method. On the Hand-held versions of Antibiotic Kinetics©, this method is designated by the abbreviation "B".

The serum level time is relative to the preceeding dose. For example:

The timing of the trough level is therefore 10.5 hours after the end of the infusion.

One way to grasp this concept is to understand that the serum level is the result of a dose which has been given, not from a future dose.

Why does the creatinine clearance from the Antibiotic Kinetics© program differ from what I calculate by hand?

The difference is most likely due to the weight that you are using in your hand calculation. Because creatinine is produced by muscle tissue, C&G recommend that you use lean body weight, except in morbidly obese patients. Because creatinine is produced by muscle tissue, not fat, additional weight in form of fat does not significantly alter the production of creatinine.

There is considerable difference of opinion among practitioners concerning the most appropriate creatinine clearance equation to use. Antibiotic Kinetics© includes multiple creatinine clearance methods from which to choose. Use the method which is most appropriate for your patient. Please refer to this page for more information on creatinine clearance calculations:

How do I dose IM gentamicin?

Enter an infusion length of 90 minutes, which is the average time for IM absorption of aminoglycosides. Be sure to draw your peaks at least 90 plus 15 minutes after the injection.

Must I always use steady-state analysis? For example, my patient received 2 doses of 1gm vanco q12hr, and for some reason the dose was decreased to 600mg around which levels were drawn.

You do not have to assume steady-state if you use the 3-point method. Draw a trough before the 600mg dose, a peak after, then a mid-point level after that. The program will use the pre-dose trough and the peak level to calculate the volume of distribution. The two post-dose levels are used to calculate the elimination rate.

Why is the default dose for once-a-day gentamicin 5mg/kg instead of Hartford's 7mg/kg?

Please refer to this consensus document which appeared in the June 1997 issue of the International J. of Clinical Pharmacology and Therapeutics:

During prospective dosing of pediatric patients there seems to be no way to chose an initial target peak/trough value like there is for adults.

The initial pediatric calculations are weight based, as they are in every pediatric reference book you will find. Although you cannot target a specific peak and trough, the program will show estimated peak and trough levels from your selected dose.

The reason that initial doses are weight-based is because the creatinine clearance equations for peds are not accurate enough to be used for pk modeling.

Do I enter serum level times relative to the beginning or the end of the infusion?

Times are relative the beginning and the end of the infusion.

How does the program handle late doses?

Unfortunately, late doses can not be avoided, so how can you use these levels? There are at least two late dose scenarios, each would be handled differently, depending on the methodology you are using.

The first late dose scenario we'll describe occurs if the dose was late but the levels were correctly drawn relative to the actual hang time. For example, the nurse is supposed to be giving gent 80mg Q 8 hours, at 6-14-20, but the sample dose is given late, at 1600. The trough was drawn at 1530 and the peak at 1730. As you can see, the levels are correctly drawn relative to the late dose.

First, let's examine the Sawchuk and Zaske method. This method is the gold standard for evaluation of peak and trough levels in the one-compartment open model. Sawchuk and Zaske drew three levels: a trough before the dose, a peak after the dose, and another trough after the dose. However, many institutions take a shortcut and only draw two levels, a trough before the dose and a peak after. If the patient is at steady-state, then you can assume that the second trough after the dose will be the same as the trough before the dose. Under most circumstances, this is a valid assumption and will save laboratory expenses.

Next, look at Sawchuk and Zaske's equations for calculating pk parameters, you can find them in the program help file (Press the F1 key). Where is the dosing interval in these equations? ...... nowhere! The dosing interval is not used in any calculation.

If you are using the 3-point method, the interval is not used, and it doesn't matter if the dose was given late, as long as the levels are correctly drawn, relative to the time the dose was actually given.

If you are using the two point method, the dosing interval is only used to extrapolate the pre-dose trough to simulate the after-dose trough. Therefore, in the Antibiotic Kinetics program, instead of entering the "ordered" interval, you would enter the time between the last dose and the sample dose. Using our same example, if the nurse is supposed to be giving gent 80mg Q 8 hours, at 6-14-20, but the sample dose is given late, at 1600. In the Antibiotic Kinetics program you would enter an interval of 10 hours. Again, this is because the interval is only used to extrapolate the pre-dose trough.

The second late dose scenario occurs when the dose is give late and the levels are correctly drawn relative to the scheduled hang time, not the actual hang time. For example, if the nurse is supposed to be giving gent 80mg Q 8 hours, at 6-14-20, the sample dose is given late, at 1600, but the trough was drawn at 1330 and the peak at 1530. As you can see the levels are correctly drawn relative to the scheduled dose, not the actual hang time, the "peak" is not a peak at all, but a trough drawn before the dose was given.

This scenario is the result of a lack of communication between lab and nursing. In this case, throw out the peak and just use the trough. With Bayesian you only need a single trough level.

The Antibiotic Kinetics program is deceptively simple in this area. When you hit a snag like this, you have to stop and think, and that's the downside to having such a simple interface for entering levels. The other alternative, and the one taken by most other PK programs, is to have you enter each and every dose and the time each dose was administered. This approach punishes you each time you have to enter a simple set of levels. The Antibiotic Kinetics program only makes you work hard in a problem situation.

How do I enter my own drug model?

The model editor is accessed from the program menu:

Where I can find linear regression equations for beta-lactam antibiotics? I'd like to be able to get a good set of Kel values to plug in for cephalosporins and penicillins.

Unfortunately, this information is not found in one single reference. Bennett's Drug Prescribing in Renal Failure and Chernow's Critical Care Pharmacotherapy have tables of pk data for common drugs. The FDA package insert of newer drugs usually has an excellent pharmacokinetics section.

For a detailed tutorial on creating one compartment models, please see this page:

The following page contains a table of pk parameters for common antibiotics:

My patient is a double amputee, the program won't let me enter his height (36"), what should I do?

The program does not make any specific adjustments for amputees, so you'll need to do some calculations the old-fashioned way. Enter the patient's pre-amputation height. The program will calculate a baseline lean body weight.

Because creatinine is produced by lean tissue, to get a more accurate estimate of CrCl, you'll need to estimate post-amputation muscle mass. Start with the LBW calculated from the patient's pre-amputation height. Then deduct a percentage depending on the extent of the amputation:

In this case, since your patient is a double amputee, you would decrease the LBW by 32%. Let's call this the Amputee-Adjusted LBW (AALBW).

If the patient's actual weight is less than the AALBW, then the patient is underweight and you should use the patient's current weight to calculate CrCl.

If the patient weighs more than the AALBW, then you should hand calculate the CrCl using the AALBW.

References

  1. John Murphy's Clinical Pharmacokinetics, 2nd ed. 2001
  2. Brunnstrom, S. Clinical kinesiology. 4th ed. 1983

My patient is bedridden and I cannot obtain his/her height, what should I do?

Good question. A patient may also have scoliosis or severe contractions that prevent a true height measurement. There are (at least) three methods that may be used to estimate height when actual measurement is not possible: knee height, forearm length and demi-span.

Does Antibiotic Kinetics run on an Apple Macintosh (iMac) computer?

We do not currently offer a native Mac version of Antibiotic Kinetics, however, please try the Web version which runs in the Safari web browser, it works perfectly on the iMac:

Does Antibiotic Kinetics run on an Apple iPhone?

Yes, there are versions available for the iPhone, please see the following for options:

Please explain the information displayed in the "Bayesian Results" dialog after Bayesian serum level analysis.

The "Bayesian Results" dialog displays several parameters which are used to evaluate the accuracy, reliability, and expected performance of the Bayesian derived model.

 


Desktop FAQs

Does Antibiotic Kinetics© run on 64-bit Windows 7?

Yes.

All versions of 64-bit Windows (XP, Vista, 7, 8, 8.1) are able to run 32-bit programs seamlessly through WOW64 which is provided with the operating system and does not have to be explicitly enabled. In other words, it's 100% automatic. (Ref: Microsoft)

According to Microsoft, 32-bit software running under WOW64 has a similar performance when executing under 32-bit Windows. (Ref: Microsoft)

Does Antibiotic Kinetics interface with our Pharmacy Information System?

Antibiotic Kinetics© may be interfaced with a PIS, using our open interface specification. Please contact your PIS vendor to request implementation.

The built-in help displays the message "Navigation to the web page cancelled", instead of the actual help information. The program is installed on our network.

The Antibiotic Kinetics© help file is a Windows compiled help file. For security reasons Microsoft has disabled viewing of CHM files over networks.

Please be aware that Antibiotic Kinetics is not network enabled, you may run into issues if you have multiple users accessing the program.

New versions of AbPK copy the help file into your local user folder. So, the fix is to upgrade AbPK.

Otherwise, you may read the the help on this web site:

How and where do I download and install the update?

Antibiotic Kinetics© has had a built-in update checker since version 2.3.1, it is accessed via the Help menu:

Antibiotic Kinetics update

There are four steps to the web update process.

  1. Click Check button to access the RxKinetics web site to check for available updates.

    Web update

  2. If an update is available, a confirmation dialog will appear. Click the "Yes" button.

    Web update

  3. Next, a change log dialog is displayed.

    Web update

  4. A running program cannot be replaced.
    Therefore, you must exit Antibiotic Kinetics before installing an update. Web update will not proceed with the install step until you close Antibiotic Kinetics.
    After you have closed the Antibiotic Kinetics program, click the "OK" button to begin the update process.

    Web update

Where do I find what functions have changed in the latest version?

Antibiotic Kinetics© version history

 


PDA problem solutions

The serial number you sent me doesn't work!

Your serial number is calculated specifically for your PDA, based on the information you provide us.

You must supply these names exactly as they appears on this screen. Case, spaces and punctuation are all relevant. We will gladly re-calculate your serial number with the correct information, just ask!

What is the serial number to download the update?

No serial number is necessary to download Antibiotic Kinetics.

 


PalmOS FAQs

Why does the Palm version run so slow?

Yes, the Palm version runs slow on older, inexpensive devices like the Visor Deluxe or the Palm M105. These cheaper Palm devices use a very slow processor (Motorola Dragonball), which works fine for keeping track of appointments, but is slow when performing complex math functions.

I have used a speed hack called "AfterBurner" with these slow old Palms (available from PalmGear). The speed difference is noticeable, but not dramatic. Otherwise, if you have the need for speed, buy a new Tungsten, they scream.

AbPK for Palm OS has become unregistered!

You may have inadvertently changed your device indentification. Your registration code is specifically tied to your Palm HotSync ID. Therefore, if you change the device ID, you will need to get a new registration code.

You may request a new code from RxKinetics by sending an email with your old user name and your new user name (include as much information as possible for fastest processing - please provide your original order number to speed up the process).

Another simple solution is to just reset your Palm HotSync ID back to its original value. The following procedure will allow you to change your HotSync ID without affecting anything you have installed on your Palm device:

  1. Run the Palm Desktop application
  2. Select USERS from the TOOLS menu
  3. Click on your HotSyncID in the list to select it
  4. Click the RENAME button.
  5. Type in your new/correct HotSyncID now very carefully
  6. Click OK to return to the USERS Dialog
  7. Click OK to exit out of the USERS Dialog
  8. Exit out of the Palm Desktop Application
  9. Do a regular HotSync - this will copy your corrected name down to your Palm device.
You will now be able to use your original registration code.

I replaced my old Palm PDA with a new Palm, will you give me a new registration code?

You may request a new code from RxKinetics by sending an email with your old user name and your new user name (include as much information as possible for fastest processing - please provide your original order number to speed up the process).

However, my advice to users replacing their Palm is to keep the same HotSync ID. When you use the same ID, HotSync will automatically transfer all your data (calendar, contacts, etc) AND all your software to your new Palm.

The following procedure will allow you to change your HotSync ID:

  1. Run the Palm Desktop application
  2. Select USERS from the TOOLS menu
  3. Click on your HotSyncID in the list to select it
  4. Click the RENAME button.
  5. Type in your new/correct HotSyncID now very carefully
  6. Click OK to return to the USERS Dialog
  7. Click OK to exit out of the USERS Dialog
  8. Exit out of the Palm Desktop Application
  9. Do a regular HotSync - this will copy your corrected name down to your Palm device.
You will now be able to use your original registration code.

 


Windows Mobile FAQs

The program doesn't run on my fancy new Windows Phone.

If you have the new Windows Phone 7 or 8, the only current option is the web app here:

AbPK for Windows Mobile has become unregistered!

You may have inadvertently changed your device indentification. Your registration code is specifically tied to your device owner name. Therefore, if you change the device ID, you will need to get a new registration code.

You may request a new code from RxKinetics by sending an email with your old user name and your new user name (include as much information as possible for fastest processing - please provide your original order number to speed up the process).

Another simple solution is to just reset your device owner name back to its original value. The following procedure will allow you to change your device owner name without affecting anything you have installed on your PDA:

  1. Tap "Start" then tap "Today"
  2. Tap the word "Owner" on your PDA
  3. Correct the Name
  4. Tap "OK"
You will now be able to use your original registration code.

I am getting a 'File pointer has reached end of file' error on my Windows Mobile device.

One of the database files has become corrupted. To fix the error, exit AbPK and erase the data files, they will be re-created when you re-start AbPK.

  1. Exit out of AbPK.
  2. Tap "Start", then "Programs" then "File Explorer"
  3. Navigate to \Program Files\Antibiotic Kinetics
  4. Tap and hold on the file "abpk_patient" then Tap "Delete"
  5. Tap and hold on the file "abpkmodels" then Tap "Delete"
When you restart Antibiotic Kinetics it will re-create these files.

There appear to be multiple copies of AbPK running on my Windows Mobile SmartPhone.

This is a known issue with version 1.x of AbPK for Pocket PC running on Windows Mobile (5 and up).

We recommend that you upgrade to version 2.x of AbPK for Windows Mobile (5 and up).

Another workaround to this problem is to use a task switching program. Once activated, the task switcher icon on the task bar enables you to see what programs are currently running on your PDA and provides a way to switch between running programs (and to shut down applications).

Some PDA manufacturers, like Dell, provide their own task switching program. If your PDA did not come with a task switcher, HandySwitcher is a 3rd party tool which works in a similar manner.

My Treo SmartPhone does not have a Tab key, how do I move between data entry fields without tapping each one?

To duplicate the Tab key function, hold the shift key down while pressing the space bar.

When I run AbPK on my iPAQ 2795 I get an application error "cannot find extension file pvbDecl.dll".

Please download version 2.x which was specifically designed for Windows Mobile.

 


Android FAQs

When I tap on the AbPK icon on the home screen, it takes me to the main screen.

To switch between tasks on Android, perform a long press on the Home button, the task switcher will appear:

Tap on the AbPK icon in the task switcher to go back to where you left off.

The screen does not rotate when I slide out the keyboard on my Motorola Droid.

Yes, all screens, except the graph, are currently fixed in portrait mode. The GUI portion of Android SDK is very complex, every widget has to be hand-coded. I haven't had the time yet to redraw every screen for a landscape rotation, that will come in future versions. Please use the app in portrait mode. To edit a field, tap it and the software keyboard will popup. It's not a bug, it's a feature!

Sometimes when I rotate the phone from horizontal to vertical and visa versa, the program goes back to opening screen. Nothing is lost, it just shows the opening screen again.

This is called a "nag" screen, you do not see this in the paid version. The purpose of a "nag" screen is to irritate you, and motivate you to purchase the paid version. I've spent six months of my life, working 10 hours a day to get this application out there. I don't think anybody works for free, do you? If you are using the app, please support my programming efforts. Your conscience and I will thank you.

I cannot see the buttons on the bottom of the serum level entry screen.

With the "Jellybean" version of Android, Google added a new font size setting called "Huge". This font size is not compatible with AbPK. To fix:

1. Tap "Settings"

settings

2. Tap "Display"

display

3. Tap "Font size"

font-size

4. Select "Large" (or Normal)

font-large

Thanks to David Jones for finding this out.

The screen does not rotate when I slide out the keyboard on my Motorola Droid.

Yes, all screens, except the graph, are currently fixed in portrait mode. The GUI portion of Android SDK is very complex, every widget has to be hand-coded. I haven't had the time yet to redraw every screen for a landscape rotation, that will come in future versions. Please use the app in portrait mode. To edit a field, tap it and the software keyboard will popup. It's not a bug, it's a feature!

I recently bought a Samsung device. Now when I open up Antibiotic Kinetics I get a floating keyboard instead of my regular keyboard. The floating keyboard doesn't let you enter decimal points.

This is a known and often complained about problem with some Samsung devices.

The Samsung numeric keyboard looks like a phone call pad with no decimal point:

Samsung numeric pad

The workaround is to download a new keyboard app and set it as the default instead of Samsung. The Google keyboard is free:

Google numeric pad

Download the standard Google keyboard from the Play store

Then, in the language and input settings, make the Google keyboard the default.

My Samsung S5 does not have a menu "button". How do I change the AbPK settings and pk models?

The Samsung Galaxy S5 still has a menu button, it's just hidden. You only have to know where to look for it. Press and hold the multitasking key until the menu pops up. That's literally all there is to it. No black magic, it's just hidden behind the very button that replaced it.

Here is a youtube video if you need visual help with finding it:


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