Adapalene (Differin) is a topical retinoid that is used primarily for the treatment of acne. Adapalene is one of the most commonly used topical retinoids. Adapalene is a synthetic, third-generation retinoid that has better efficacy and safety profiles than older topical retinoids (eg. Isotretinoin, Tretinoin). This medication is now available as an Over-The-Counter (OTC) product in some regions.
Retinoids are derivatives of Vitamin A. Retinoids can help improve acne symptoms in several ways. Retinoids decrease the activity of the sebaceous glands, which decreases the production of sebum. The decrease in sebum in eliminates decreases the amount of nutrients that are available for for acne-causing bacteria, such as P. acnes. Retinoids can also affect the growth and differentiation of skin cells, which can help reduce the formation of clogged pores (comedomes). Retinoids also have anti-inflammatory affects which may help improve acne symptoms.
Multiple clinical research studies indicate that Adapalene has similarly effective for treating acne as another common topical retinoid, Tretinoin, but has milder side effects. Adapalene works by entering target cells and binding to to specific receptors called Retinoic Acid Receptors that are in the nucleus of cells. Once the retinoid binds to these receptors it changes how the genes of that cell are expressed. These changes in gene expression are what give retinoids their anti-acne properties.
Adapalene can be a valuable treatment for individuals with any type of acne (Acne Types: 1-4). Adapalene can improve acne symptoms for many patients, but complete resolution of acne symptoms is rare when Adapalene is used alone. Adapalene is frequently combined with complementary acne treatments (eg. Antibiotics, Androgen Inhibitors, Light & Laser therapies, etc). Adapalene and other topical retinoids tend to be more effective for the treatment of mild acne and less effective for moderate and severe forms of the disease.
There are many topical medications available that combine Adapalene with a second antibacterial agent. Adapalene is widely available in combination treatments with Benzoyl Peroxide (Epiduo), Clindamycin (Lacne) and Azithromycin (ATM-A).
The most common side effect of Adapalene treatment is dryness of the skin. Adapalene treatment decreases the production of sebum, and sebum is essential for moisturizing and protecting the skin. Most retinoid treatments cause dry skin, but Adapalene tends to have milder side effects than other topical retinoids, such as Tretinoin and Isotretinoin. The most serious potential side effect of Adapalene is a risk of birth defects. All retinoids are teratogens (compounds that can cause birth defects). However, several studies have indicated that their is minimal risk to the fetus from the topical use of retinoids, including Adapalene. Nonetheless, the use of any type of retinoid is generally avoided in all women who are pregnant or may become pregnant during treatment.