RxOnTap - Prescriptions on Tap - Rapid Prescription Writer for the Newton MessagePad. Rx on Tap is a timesaving program for the Newton MessagePad and Sharp ExpertPad. Using Rx on Tap, any given prescription, no matter how complicated, is only a few pen taps away. No longer will you have to scribble out those complicated instructions for tapering a medication over the course of weeks. No more phone calls from the pharmacist who is trying to decipher your hieroglyphics. Rx on tap also incorporates a weight based dosage calculator and notes. This version of Rx on Tap will work for 21 days unless registered.