DoseChecker

DoseChecker is the first and only app that helps clinicians develop a safe dosing regimen for hydroxychloroquine. Tested and approved by physicians from the Harvard-affiliated hospitals Massachusetts Eye and Ear Infirmary and Massachusetts General Hospital, this app is intended for use by physicians and other health care providers who prescribe hydroxychloroquine to their patients or who monitor the ocular effects of this medication on their patients.
1.	The app uses the Actual Body Weight method, following American Academy of Ophthalmology 2016 guidelines. 
2.	The app uses an adjustable weekly dosing schedule.  Instead of placing the patient on either 400 mg per day or 200 mg per day (the drug comes only as a 200 mg tablet), the app suggests a weekly dosing regimen using a combination of 400 mg and 200 mg daily doses.  This dosing regimen will yield the highest therapeutic dose attainable without exceeding the toxic limit defined by the Actual Body Weight method. 
The DoseChecker app is simple to use.  The clinician just enters the patient’s weight in pounds or kilograms and touches the calculate button.  The recommended weekly dosing appears immediately.  In addition, the dosing recommendations always fall within the approved drug labeling (which also obviates the need for FDA mobile medical app registration).  Thus, all physicians can use the app to rapidly and efficiently determine the safest dose of hydroxychloroquine--the most important step in preventing irreversible vision loss from hydroxychloroquine retinopathy.  
How to use DoseChecker:
1.	Download from the App Store and install in your iPhone. (If the top letters in the app are not “DoseChecker” in large white text, then rotate the phone 90 degrees (horizontal position) and then back to vertical. The title should appear.
2.	If you want to use the metric system for patient data entry, tap the Disclaimer/Change to Metric button.  Then tap Metric button.  Phone will stay in metric mode unless the power is turned off.
3.	Blinking cursor is at left of Weight entry text box.  Enter the patient’s weight in pounds or kg.  Tap “return”
4.	Blinking cursor is to the right of the default entry for patient’s current Dose (400 mg).  If this correct, just tap “return”.  The only time you would change the entry is if the patient was on 200 mg daily; then you would replace the 400 with 200 and tap “return”.
5.	Once you have entered the data in the textboxes, you can go back as needed if there are errors.  Once you are satisfied the entries are correct, tap the CALCULATE button.  
6.	Tap “RESET” to do another patient.
NOTES:
     • To start a patient out on hydroxychloroquine, leave the default dose at 400 mg.  Then you can see what the maximum dosing should be for that patient.
     • A weekly Dosing Schedule is recommended to allow the highest possible therapeutic level without exceeding the toxic dosing level. The Dosing Schedule always puts the lower doses (200 mg) at the end of the week. Thus it might recommend 400 mg daily Monday through Friday, and then 200 mg Saturday and Sunday.  Of course, you could set the 2 lower days any time during the week for convenience (eg Monday and Thursday, if the patient finds that easier to remember).