Transcript Phonophoresis - Therapeutic Modalities

Phonophoresis
Description
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Use of therapeutic ultrasound to assist in
diffusion of medication through the skin
Increases the diameter of skin portals to allow
the medication to pass
Pores
 Hair follicles
 Sweat glands
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© 2005 – FA Davis
Biophysical Effects
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Medication is introduced over a large area
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Relative to an injection
Noninvasive
Medication may not be filtered by the liver
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Reducing metabolic elimination of the medicine
© 2005 – FA Davis
Transdermal Application
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Medication must diffuse through:
Enzymatic barrier of the epidermis
 Stratum corneum
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Rate-limiting barrier to absorption
 Medications must be able to diffuse across this barrier
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Medication is stored in subcutaneous tissues for
some time before being diffused deeper
© 2005 – FA Davis
Skin Influences
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Medication uptake is improved when the skin is:
Well hydrated
 Has a high density of skin portals
 Highly vascularized
 Relatively thin
 “Younger” skin tends to have better diffusion
characteristics than “older” skin.
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© 2005 – FA Davis
Ultrasound Influences on Diffusion
Thermal Effects
 Increase kinetic energy
 Increase portal cross-section
 Increase circulation
 Increase capillary permeability
Nonthermal Effects
 Altered cell resting potential
 Increased cell membrane permeability
 Increased molecular permeability
© 2005 – FA Davis
Phonophoresis Medications
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Either prescription or nonprescription
Low molecular size and weight
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Most medications used can be applied transdermally
without ultrasound
Controlled medications require a prescription
for the patient being treated
Medication is often mixed in an inert base
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Base must be able to transmit ultrasonic energy
© 2005 – FA Davis
Common Medications
Type
Corticosteroid
Indications
Inflammation
Salicylates
Inflammation
Pain
Pain
Trigger points
Anesthetic
© 2005 – FA Davis
Example
Hydrocortisone
Dexamethasone
Lidocaine
Application Tips
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Moist heat pack prior to application:
Increase blood flow
 Increase kinetic energy
 Increase skin portals
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Following treatment
Leave medication on skin
 Cover with an occlusive dressing
 Moist heat pack re-application may assist in further
absorption
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© 2005 – FA Davis
Low-frequency US Phonophoresis
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Parameters:
20 kHz output frequency
 125 mW/cm2
 Pulsed output
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Benefits:
Allows medications with a larger size and weight to
diffuse
 More efficient medication delivery
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© 2005 – FA Davis