ALA-SCALP
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ALA-SCALP (ALA-SCALP).
ALA-SCALP (aminolevulinic acid) is a photosensitizer precursor that is converted intracellularly to protoporphyrin IX (PpIX), which accumulates in cells with increased heme synthesis, such as rapidly dividing cells. Upon exposure to blue light (BLU-U®), PpIX produces reactive oxygen species, leading to cellular damage and apoptosis of targeted cells.
| Metabolism | ALA is metabolized intracellularly via the heme biosynthesis pathway to protoporphyrin IX (PpIX). |
| Excretion | Primarily renal elimination of metabolites; <1% excreted unchanged in urine. Biliary/fecal excretion is negligible. |
| Half-life | Not applicable; topical ALA-SCALP is not significantly absorbed systemically. After systemic absorption from photodynamic therapy, terminal half-life is approximately 1 hour due to rapid metabolism. |
| Protein binding | Not characterized; systemic levels are negligible after topical administration. |
| Volume of Distribution | Not applicable for topical route. If systemic exposure occurs, Vd is approximately 0.5 L/kg, consistent with distribution into total body water. |
| Bioavailability | Topical: Systemic bioavailability is minimal (<1%) due to poor percutaneous absorption and rapid local metabolism. |
| Onset of Action | Topical: Erythema and edema appear within 30–60 minutes after light activation; clinical effect (tumor response) develops over 24–48 hours. |
| Duration of Action | Duration depends on disease and treatment parameters; lesion clearance may persist for weeks. Acute phototoxic reactions resolve within 1–2 weeks. |
Topical application of a 5% solution to the scalp twice daily.
| Dosage form | LOTION |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established. |
| Geriatric use | No specific dose adjustment recommended; use with caution due to potential increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ALA-SCALP (ALA-SCALP).
| Breastfeeding | Minimal systemic absorption; unlikely to appear in breast milk. M/P ratio not established. Considered compatible with breastfeeding. |
| Teratogenic Risk | No evidence of teratogenicity; topical application with minimal systemic absorption. First trimester: unlikely risk. Second/third trimester: no known fetal risks from maternal use. |
| Fetal Monitoring | None specifically required. Monitor for local skin reactions or signs of systemic effects (rare). |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to aminolevulinic acid or any component of the formulation","Cutaneous photosensitivity at wavelengths of 400-450 nm","Porphyria"]
| Precautions | ["Photosensitivity: avoid exposure to sunlight or bright indoor light (e.g., examination lamps, operating room lamps) for at least 40 hours post-application.","Application site reactions: severe stinging, burning, erythema, and edema may occur.","Use sun-protective measures (e.g., wide-brimmed hat, sunscreen) after treatment.","Do not apply to eyes or mucous membranes."] |
| Food/Dietary | No known food interactions. No dietary restrictions required. |
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| Fertility Effects | No known effects on fertility. Topical formulation minimizes systemic exposure. |
| Clinical Pearls |
| ALA-SCALP is a topical aminolevulinic acid preparation used for photodynamic therapy of actinic keratoses on the scalp. Must be applied by a healthcare professional. Avoid sun exposure to treated area for 48 hours post-application due to photosensitivity. Do not apply to eyes or mucous membranes. Lesions should be prepped by gentle removal of scales and crusts. Use with a compatible light source (blue light). Burning and stinging during light exposure is common; consider pain management strategies. |
| Patient Advice | This medication is applied by your doctor to treat precancerous spots on your scalp. · After application, you will need a special light treatment (photodynamic therapy). · Avoid sunlight and bright indoor light on the treated area for 48 hours after the procedure. · You may experience temporary redness, swelling, scaling, or discomfort at the treatment site. · Use sunscreen and protective clothing when going outdoors during the photosensitivity period. · Do not wash the treated area for at least 4 hours after the solution is applied. · Contact your doctor if you experience severe pain, blistering, or signs of infection. |