Aminolevulinic Acid (Monograph)

Brand name: Levulan
Drug class: Skin and Mucous Membrane Agents, Miscellaneous
ATC class: L01XD04
VA class: DE350
Chemical name: 5-Aminolevulinic acid hydrochloride
Molecular formula: C₅H₉N_O3•HCl
CAS number: 5451-09-2

Introduction

Photosensitizer; hydrochloride salt of 5-aminolevulinic acid, an endogenous precursor of protoporphyrin IX.

Uses for Aminolevulinic Acid

Nonhyperkeratotic Actinic Keratoses of Face or Scalp

Treatment of minimally to moderately thick (nonhyperkeratotic) actinic keratoses of the face or scalp, in conjunction with blue light illumination using the BLU-U Blue Light Photodynamic Therapy Illuminator (BLU-U).

Aminolevulinic Acid Dosage and Administration

General

• Topical solution should be applied only by qualified medical personnel.

• Apply topically to individual actinic keratosis lesions on either scalp or face, but not both simultaneously. Do not apply in or around eyes or mucous membranes or to perilesional skin.

Administration

Topical Administration

Preparation of the Applicator

With the applicator cap pointing up, sequentially break the 2 glass ampuls within the plastic applicator by applying finger pressure to appropriate position on the bottom ampul (vehicle solution), then the top ampul (powdered drug).

With applicator cap pointed away from face, shake applicator gently for at least 3 minutes to completely dissolve the drug in the vehicle. Do not press on end cap while shaking.

Topical Application

Apply topically; use within 2 hours because of the instability of the activated product. If application of the solution is not completed within 2 hours of activation, discard applicator and use a new one.

Clean and dry lesions prior to application of solution.

Gently dab target lesions directly with wet applicator tip, uniformly wetting lesion surface, including the edges, without excess running or dripping.

Allow application to dry and then reapply one time in the same manner.

Illumination of Treated Lesions

14–18 hours after application, gently rinse target lesions with water, pat dry, and photoactivate with blue light illumination from the BLU-U Blue Light Photodynamic Therapy Illuminator.

Patients and medical personnel should use blue light-blocking protective eyewear during BLU-U illumination.

Solution is not intended for use with any device other than the BLU-U Blue Light Photodynamic Illuminator.

Dosage

Adults

Actinic Keratoses

Topical

Apply solution to lesions as directed (See Topical Application under Dosage and Administration); allow to dry and reapply once. 14–18 hours later, expose affected areas to BLU-U illumination for 1000 seconds [16 minutes, 40 seconds].

After 8 weeks, apply solution a second time to lesions that have not completely resolved.

Related/similar drugs

diclofenac topical, fluorouracil topical, imiquimod topical, Efudex, Santyl, Aldara, tirbanibulin topical

Cautions for Aminolevulinic Acid

Contraindications

• Known cutaneous photosensitivity at wavelengths of 400–450 nm.

• Known porphyria or known allergies to porphyrins.

• Known sensitivity to aminolevulinic acid or any ingredient in the formulation.

Warnings/Precautions

Warnings

Topical Application Only

Solution contains alcohol; for topical use only. Do not apply in or around the eyes or to mucous membranes. May cause excessive irritation if applied under occlusion.

General Precautions

Application by Health Professional

Only qualified medical personnel should apply solution; application to perilesional area of face or scalp may result in photosensitivity.

Photosensitivity Reactions

Sites will be photosensitive after topical application of solution; stinging and/or burning sensation, erythema, and/or edema of lesions may occur with exposure to bright light.

Avoid exposure of treated sites to sunlight or bright indoor light (e.g., examination lamps, operating room lamps, tanning beds, lights at close proximity) prior to blue light photoactivation.

Protect treated lesions from sun by wearing a wide-brimmed hat or similar head covering of light-opaque material, and keep lesions dry. Sunscreens will not protect against photosensitivity reactions caused by visible light.

Reduce exposure to light if stinging and/or burning occurs.

Dermatologic Reactions

Following photoactivation with blue light, reddening, swelling, and scaling of treated actinic keratoses and surrounding skin may occur.

Lesion changes usually resolve completely within 4 weeks after treatment.

Delay in Receiving Blue Light Treatment

Patients should contact clinician if they cannot return for blue light treatment 14–18 hours after application of solution.

Patients should continue to avoid exposure of photosensitized lesions to sunlight or prolonged or intense light for ≥40 hours after solution application.

Specific Populations

Pregnancy

Category C.

Lactation

Not known whether aminolevulinic acid is distributed into milk; use caution.

Common Adverse Effects

Transient local stinging and/or burning, itching, erythema, edema, scaling/crusting, itching, hypopigmentation/hyperpigmentaion, erosion, skin disorder (unspecified), wheal/flare, vesiculation.

Drug Interactions

No formal drug interaction studies performed. No drug-specific interactions noted during controlled clinical trials.

Other Known Photosensitizing Agents

Potential pharmacologic interaction (increased photosensitivity reaction) with other known photosensitizing agents (e.g., griseofulvin, thiazide diuretics, sulfonylureas, phenothiazines, sulfonamides, tetracyclines).

Aminolevulinic Acid Pharmacokinetics

Absorption

Bioavailability

50-60% after a 128-mg oral dose of aminolevulinic acid hydrochloride (equivalent to 100 mg of aminolevulinic acid).

Distribution

Time to Peak Fluorescence

Peak fluorescence intensity for protoporphyrin IX (metabolite of aminolevulinic acid) reached at approximately 11 or 12 hours in actinic keratoses or perilesional skin, respectively.

Elimination

Half-life

0.83 or 0.7 hours with a 128-mg aminolevulinic acid hydrochloride IV or oral dose, respectively.

Mean fluorescence half-life of 30 or 28 hours in lesions or perilesional skin, respectively.

Stability

Storage

Topical

Solution

20–25°C; excursions permitted to 15–30°C. Discard reconstituted solution 2 hours after mixing.

Actions

• Metabolism of aminolevulinic acid is first step in synthesis of heme, which is formed when iron (under action of ferrochelatase) is incorporated into protoporphyrin IX.

• Synthesis of endogenous aminolevulinic acid (ALA) tightly controlled by feedback inhibition of ALA synthetase, presumably by intracellular heme levels.

• Following topical application of aminolevulinic acid, it is converted into protoporphyrin IX (a photosensitizer), which accumulates in skin due to limited capacity of ferrochelatase to convert protoporphyrin IX into heme.

• When exposed to light of appropriate wavelength and energy, accumulated protoporphyrin IX produces a photodynamic reaction.

• Tissue-specific phototoxic effects result from generation of cytotoxic singlet oxygen atoms, which form superoxide and hydroxyl radicals.

Advice to Patients

• Aminolevulinic acid hydrochloride topical solution is not meant for application by patient. Only qualified health professionals should apply drug.

• Importance of advising patient to keep lesions dry and out of bright light following application of the topical solution.

• Importance of informing patient of possible transient stinging and/or burning at treated lesion sites if exposed to bright light following topical solution application; patient should reduce exposure to light if this occurs. Importance of patient wearing light-protective clothing, such as a wide-brimmed hat or similar head covering of light-opaque material, before going into sunlight following topical solution application. Importance of informing patient that sunscreens will not protect against photosensitivity reactions caused by visible light. Importance of patient limiting exposure to bright indoor light following topical solution application.

• Importance of informing patient that transient tingling, stinging, prickling, and/or burning may occur at target lesion sites during period of blue light photoactivation.

• Importance of patient informing clinicians of existing or contemplated therapy, including prescription and OTC drugs.

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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