Dosing and uses of Metvixia (methyl aminolevulinate)
Adult dosage forms and strengths
cream
- 16.8%
Actinic Keratosis
Indicated in conjunction with photodynamic therapy for treatment of minimally to moderately thick actinic keratoses of the face or scalp
Apply product only by a qualified physician, NOT patient or unqualified healthcare personneL
Metvixia
- Apply on skin with spatula about 1 mm thick to lesion and surrounding 5 mm of normal skin, not to exceed >1 g per session
- Cover area with occlusive non-absorbent dressing for 3 hr
- Treatment area not to exceed 80 x 180 mm
- Within 4 hr of application, remove dressing, rinse off cream, and perform red light (57-670 nm) photodynamic therapy (total light dose 75 J/cm²)
- Repeat once after 7 days; assess response 3 months after the last treatment session
Pediatric dosage forms and strengths
Not recommended
Metvixia (methyl aminolevulinate) adverse (side) effects
>10% (with Aktilite PDT illum)
Skin burning/pain/discomfort (86%)
Erythema (63%)
Scabbing/crusting/blisters (29%)
Pruritus (22%)
Skin or eyelid edema (18%)
Skin exfoliation (14%)
1-10%
Skin warm (4%)
Application site discharge (2%)
Skin hemorhage (2%)
Skin hyperpigmentation (2%)
Skin tightness (2%)
Postmarketing Reports
Allergic reactions: Eczema, allergic contact dermatitis, and urticaria localized to treatment area; rarely erythema and swelling have been more extensive
Hypersensitivity: Angioedema, facial edema, and application site infections
Malignancies: Squamous cell carcinoma of the skin, as expected in this population
Eye disorders: Macular edema, vitreous detachment, and keratitis
Warnings
Contraindications
Cutaneous photosensitivity
Sensitivity to porphyrin or other components (contains peanut and almond oil)
Cautions
Use within 2 hr of activation
Avoid light exposure between solution application and light treatment (wear hat, etc)
Should not be applied in or around the eyes or to mucous membranes
Avoid exposure to outdoor or bright light during time between drug application and light treatment, and for 2 days afterwards
Photosensitized skin may produce a stinging or burning sensation and become erythematous similarly to actinic keratoses; to ensure drug is only applied to actinic keratoses and not perilesional skin aminolevulinic acid should be applied by qualified professionaL
Therapy never tested in patients with inherited or acquired coagulation disorders
Therapy not tested for carcinogenic risk
Cream has demonstrated high rate of contact sensitization
Effects on therapy on fertility unknown
Pregnancy and lactation
Pregnancy category: C
Lactation: unknown whether distributed in milk; use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Metvixia (methyl aminolevulinate)
Mechanism of action
Precursor of photoactive porphyrins, which accumulate in the skin lesions where the product has been applied and are subsequently illuminated with red light of narrow spectrum using a light dose of 37 J/cm² delivered by the Aktilite CL128 lamp
When exposed to the light, the accumulated photoactive porphyrins produce a photodynamic reaction, resulting in a cytotoxic process dependent on the simultaneous presence of oxygen, which as a result generates a singlet oxygen
The singlet oxygen can then react to form superoxide and hydroxyl radicals
Pharmacokinetics
Peak fluorescence: 3 hr (methyl aminolevulinate)
Half-life: 30 ± 10 hr (lesions)
