Brands, Medical Use, Clinical Data
Drug Category
Dosage Forms
- Two component system consisting of a plastic tube containing two sealed glass ampules and an applicator tip (one ampule contains 1.5 mL of solution vehicle, the other ampule contains 354 mg of aminolevulinic acid hcl as a dry solid)
Brands / Synonyms
ALA; Aladerm; delta-Aminolevulinic acid
; Kerastick; Levulan; Levulan Kerastick
Indications
Aminolevulinic acid plus blue light illumination using a blue light photodynamic therapy illuminator is indicated for the treatment of minimally to moderately thick actinic keratoses of the face or scalp.
Pharmacology
The metabolism of aminolevulinic acid (ALA) is the first step in the biochemical pathway resulting in heme synthesis. Aminolevulinic acid is not a photosensitizer, but rather a metabolic precursor of protoporphyrin IX (PpIX), which is a photosensitizer. The synthesis of ALA is normally tightly controlled by feedback inhibition of the enzyme, ALA synthetase, presumably by intracellular heme levels. ALA, when provided to the cell, bypasses this control point and results in the accumulation of PpIX, which is converted into heme by ferrochelatase through the addition of iron to the PpIX nucleus.
Mechanism of Action
According to the presumed mechanism of action, photosensitization following application of aminolevulinic acid (ALA) topical solution occurs through the metabolic conversion of ALA to protoporphyrin IX (PpIX), which accumulates in the skin to which aminolevulinic acid has been applied. When exposed to light of appropriate wavelength and energy, the accumulated PpIX produces a photodynamic reaction, a cytotoxic process dependent upon the simultaneous presence of light and oxygen. The absorption of light results in an excited state of the porphyrin molecule, and subsequent spin transfer from PpIX to molecular oxygen generates singlet oxygen, which can further react to form superoxide and hydroxyl radicals. Photosensitization of actinic (solar) keratosis lesions using aminolevulinic acid, plus illumination with the BLU-UTM Blue Light Photodynamic Therapy Illuminator (BLU-U), is the basis for aminolevulinic acid photodynamic therapy (PDT).
Absorption
Oral bioavailability is 50-60%.
Toxicity
Solution overdose have not been reported.
Biotrnasformation / Drug Metabolism
Following topical administration, synthesis into protoporphyrin IX takes place in situ in the skin.
Contraindications
The LEVULAN KERASTICK for Topical Solution plus blue light illumination using the BLU-U Blue Light Photodynamic
Therapy Illuminator is contraindicated in patients with cutaneous photosensitivity at wavelengths of 400-450 nm,
porphyria or known allergies to porphyrins, and in patients with known sensitivity to any of the components of the
LEVULAN KERASTICK for Topical Solution.
Drug Interactions
There have been no formal studies of the interaction of LEVULAN KERASTICK for Topical Solution with any other
drugs, and no drug-specific interactions were noted during any of the controlled clinical trials. It is, however,
possible that concomitant use of other known photosensitizing agents such as griseofulvin, thiazide diuretics,
sulfonylureas, phenothiazines, sulfonamides and tetracyclines might increase the photosensitivity reaction of actinic
keratoses treated with the LEVULAN KERASTICK for Topical Solution.
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