How Do Topical PDE-4 Inhibitors Work?

Topical PDE-4 inhibitors are drugs used to treat various dermatological conditions including psoriasis and atopic dermatitis. They work to suppress the immune system by inhibiting the action of an overactive enzyme called phosphodiesterases-4 (PDE-4), which helps prevent and reduce inflammation.

PDE-4 inhibitors are beneficial for people with psoriasis as they can prevent disease progression that may result in psoriatic arthritis. Around 30% of psoriasis patients eventually develop psoriatic arthritis (mild to severe joint pain).

Topical PDE-4 inhibitors work by inhibiting an enzyme “PDE-4”. PDE-4 is a key regulator of inflammatory cytokine production that converts the intracellular secondary messenger cyclic adenosine monophosphate into adenosine monophosphate, which promotes proinflammatory responses (overexpression of different inflammatory cytokines). Cytokines are proteins produced by immune cells that contribute to a normal immune response to an invading infection. When these cytokines are mistakenly triggered in the body, the resulting inflammation can develop certain diseases, including atopic dermatitis.

Topical PDE-4 inhibitors prevent disease outbreaks in the following ways:

• Blocking PDE-4 enzyme hinders the production of cytokines that are involved in the inflammation.
• Increasing a cellular signal chemical known as cyclic adenosine monophosphate (cAMP).

Topical PDE-4 Inhibitors are applied as a thin layer on the affected area twice a day.

Skin conditions treated with topical PDE-4 inhibitors include:

• Psoriasis (a skin disease that causes red, itchy scaly patches, most commonly on the knees, elbows, trunk, and scalp)
• Atopic dermatitis (a chronic skin condition characterized by dry, itchy skin)
• Psoriatic arthritis (a condition that combines the swollen, sore joints of arthritis with psoriasis)
• Chronic eczema (a condition that causes inflamed, itchy, cracked, and rough skin)
• Cutaneous lupus erythematosus (an autoimmune disease where the body's immune system attacks the healthy skin)

Common side effects include:

• Burning/and or stinging
• Dryness
• Pruritis (itchy skin)
• Pain and irritation at the affected site

Other rare side effects include:

• Hypersensitivity reactions:
  • Rash
  • Hives
  • Itching/swelling of face/tongue/throat
  • Erythema (type of skin rash caused by injured or inflamed blood capillaries)
• Contact urticaria (immediate but transient localized swelling and redness that occurs on the skin after direct contact with an offending substance)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:                         

• Crisaborle topical
• Eucrisa