Using PDT in your practice

October 19, 2008

Las Vegas - "It?s my bias that every practice should be using photodynamic therapy (PDT.) It is so useful," says C. William Hanke, M.D., M.P.H., F.A.C.P.; president, American Academy of Dermatology; visiting professor, dermatology, University of Iowa-Carver College of Medicine, Iowa City, Iowa.

Las Vegas

- "It’s my bias that every practice should be using photodynamic therapy (PDT.) It is so useful," says C. William Hanke, M.D., M.P.H., F.A.C.P.; president, American Academy of Dermatology; visiting professor, dermatology, University of Iowa-Carver College of Medicine, Iowa City, Iowa.

Photodynamic therapy is an old term, he says, for a technique where a photosensitizing drug and light combine for cellular destruction.

The two predominant PDT photosensitizers are 5-aminolevulinic acid (ALA) (20 percent 5-ALA; Levulan) (DUSA Pharmaceuticals, Wilmington, Mass.) and methyl aminolevulinate (MAL) (methylester of 5-ALA; Metvix) (Galderma), which was approved by the Food and Drug Administration (FDA) within recent weeks for the treatment of actinic keratosis (AK).

Disadvantages of PDT include incubation time, which is 10 to 18 hours for ALA and more than three hours with occlusion for MAL; pain; and healing time, which may take as long as seven days.

"This just never got off the ground," Dr. Hanke tells Dermatology Times.

Recent advances, however, have reduced contact drug interaction to 15 to 60 minutes, with minimal downtime. There is less pain associated with the procedure, as well as less downtime.

ALA PDT targets AK (roughness), oxyhemoglobin (redness) and melanin (brownness), Dr. Hanke says.

PDT is a good "field treatment" for AK, he says. The results are often dramatic.

"It is so useful and helps patients so much," Dr. Hanke says.

According to Dr. Hanke, there are 10 rules for success with short-contact PDT:

Precaution - Discontinue topical retinoids before treatment

Skin preparation issues -

  • a. Micro DA
  • b. Isopropyl alcohol
  • c. Acetone
  • d. Rubbing with gauze

ALA application

  • a. Apply fresh ALA
  • b. Apply two coats with Q-tip
  • c. Don’t drip ALA into eyes

Drug incubation - about 60 minutes

Drug activation

  • a. 417 nm blue light: 16 minutes 40 seconds
  • b. IPL: 22-25 J/cm2, double pulse
  • c. PDL: 10 mm spot, 7.5 J/cm2, 10 to 20 seconds, double pulse

Pain management during light treatment

  • a. Cool airflow
  • b. Two to five minutes rest periods during treatment
  • c. Diazepam 5 mg to 10 mg po
  • d. Topical anesthesia
  • e. Shorten incubation times
  • f. Increase distance from light

Immediate post treatment - Wash fast thoroughly with soap and water; apply sunscreen in office

Post op

  • a. Apply sunscreen for two days
  • b. May use makeup, moisturizers

Clinical course - Scaling and redness for one to four days is indication of drug activation by light

Treatment sequence

  • 1. Forehead only
  • 2. Cheeks only
  • 3. Cheeks and forehead

The patient is treated at three- to four-week intervals.

In conclusion, Dr. Hanke says, "I hope you’ll all give PDT a try." DT

Disclosures: Dr. Hanke is involved in clinical trials for Allergan, Dermik, DUSA, Galderma, Graceway, Medicis and Merz.

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