my personal edition > clinical pharmacology > news


  E-Mail this DGDispatch to a colleague

DGDispatch

Transdermal MPH Patch Will Offer Flexibility of Dosing: Presented at ASHP

By Maury M. Breecher, PhD, MPH

SAN DIEGO, CA -- June 5, 2003 -- The peaks and valleys of active drug associated with oral administration of methylphenidate (MPH) in patients with attention deficit hyperactivity disorder (ADHD) can be avoided by proper use of a once-daily MPH transdermal patch, according to a study presented here May 31^st at the American Society of Health-System Pharmacists (ASHP) annual summer meeting.

"A once daily methylphenidate transdermal system (MTS) has been developed that provides consistent and continuous delivery of d-MPH, the active enantiomer of MPH. Varying patch size and wear time permits dose titration," said senior author Mario A. González, PhD, president and CEO of GloboMax America, LLC, in Weston, Florida.

"You can't terminate the action of a sustained release form of MET while it is in the body, but with a transdermal patch you can terminate the dose at any time by simply removing the patch," Dr. González pointed out. "The MTS has been designed for 12-hour use, but it can be worn for less time depending on needs of the patient. It gives you great flexibility in dosage regimen."

"With the patch you can actually deliver smaller, but more effective dosages of MPH than you can with oral MPH medications," he continued.

According to data in the presentation, an 18-mg- dose of Concerta™ has 4.1 mg of active d-MPH. On the other hand, a 12.5 cm patch provides a 5.4-mg dose of d-MPH, the equivalent to a 5-mg twice-daily dose of oral MPH and 18-mg of Concerta™ given once a day, according to the presentation.

The presentation described a series of studies in which the pharmacokinetic properties, drug-delivery rate, and transdermal dose of d-MPH were investigated. The studies evaluated several different sizes of transdermal patches including 6.25, 12.5, 18.85, 25, 37.5, and 50 cm˛ . Conversions from MTS patch size to delivery rate and MPH transdermal dose are shown in the following table from the presentation.

"We are saying if a patient is taking a 20-mg dose of sustained release methylphenidate once a day, it can be substituted with a 12.5 cm˛ patch," said Dr. González. "Over a 12-hour period, MTS patches provide a continuous d-MPH delivery at a rate of 0.073 mg/hour/cm˛ . That's equivalent to a 5 mg MPH dose twice a day or a 20 mg MPH SR dose once a day."

"We have had studies showing that dosing over a 16-hour period in adults has been successful," he continued. "That is important because a lot children with attention deficit hyperactivity disorder (ADHD) don't outgrow the disorder. So, even as adults they need MPH treatment."

The MTS system is still awaiting FDA approval.

"This will be a promising new addition to the therapeutic armamentarium for treating children and adults with ADHD," concluded the researchers.


[Study title: Proper use of the once-daily methylphenidate transdermal system (MTS): a pharmacokinetic primer. Abstract P-30E]

E-Mail this DGDispatch to a colleague

To print, use this version