Introduction
Afamelanotide, a drug for tanning skin, is a synthetic peptide and analogue of α-melanocyte stimulating hormone. Indeed, Afamelanotide is the International Nonproprietary Name. Besides, this chemical compound is a hormone produced by the middle lobe of the amphibian pituitary used to prevent skin damage from the sun in people with erythropoietic protoporphyria (EP).
Pharmacologic action
Afamelanotide mainly acts on melanophore. The melanophores of the skin are located between the epidermis and the dermis. In the cytoplasm of the melanophore, there are many melanosomes which contain tyrosinase. The tyrosinase in the melanosome is able to promote the conversion of tyrosine into melanin. Mainly, through activated tyrosinase and promoted the synthesis of tyrosinase, the afamelanotide could promote the synthesis of melanin. Finally, the color of skin and hair is deepened.
Function
EP is a rare congenital metabolic defect and a serious photosensitive skin disease associated with acute toxicity. Tanning skin or inducing pigmentation is usually considered as an effective way to protect people with photosensitive skin diseases from sun and ultraviolet radiation. Fortunately, the afamelanotide has the power to help the patients by promoting skin melanin accumulation. On the one hand, it is able to make the patients pain-free when the duration of daylight exposure is increasing. One the other hand, the afamelanotide is capable of shortening the time the patient takes to recover from phototoxic reactions, which may last for days and would result in frequent absences from school or work. Of course, the afamelanotide can significantly reduce the number and severity of phototoxicity in adult patients with EP and significantly improve the quality of life associated with the disease. Moreover, the afamelanotide has acceptable side effects and adverse event information.
Absorption
It is administered as an implant that is placed under the skin; the implant lasts for two months. Then, it is absorbed through the skin and systemically distributed throughout the body.
References:
Grimes, P. E., Hamzavi, I., Lebwohl, M., Ortonne, J. P., & Lim, H. W. (2013). The efficacy of afamelanotide and narrowband UV-B phototherapy for repigmentation of vitiligo. JAMA dermatology, 149(1), 68-73.
Fabrikant, J., Touloei, K., & Brown, S. M. (2013). A review and update on melanocyte stimulating hormone therapy: afamelanotide. Journal of drugs in dermatology: JDD, 12(7), 775-779.
