The Phonophoresis of Lidocaine Gel and Its Effect on Sensory Blockage

The optimisation of drug absorption through skin is of great value in modern therapy.Phonophoresis is the use of therapeutic ultrasound to increase percutaneous drug absorption. However,few studies have compared pulsed and continuous modes of therapeutic ultrasound.This study compared these two modes by investigating the effect of lidocaine phonophoresis on sensory blockade. Ninety-three healthy volunteers, assigned at random to one of three ultrasound groups:pulsed(ultrasound+lidocaine),continuous(ultrasound+lidocaine)and control(sham ultrasound+lidocaine). Lidocaine was administered transdermally using a transducer.Two point discrimination, touch and maximum pain thresholds were assessed before and after the intervention in each group. Pulsed ultrasound with topical lidocaine gel induced greater anaesthetic effect compared with continuous ultrasound with topical lidocaine gel and lidocaine application alone. The mechanical properties of pulsed ultrasound appear to be responsible for greater drug penetration.