apremilast
Otezla (apremilast) is a PDE4 inhibitor from Amgen that raises levels of cyclic AMP inside immune cells, dialling down the inflammatory chemicals that drive psoriatic arthritis, plaque psoriasis, and oral ulcers in Behçet's disease. It is taken by mouth and does not require routine laboratory monitoring for organ toxicity.
This page is based on EMA, FDA, DailyMed, MedlinePlus, and NCI prescribing information for apremilast; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Inside immune cells, a molecule called cAMP acts like a volume knob on inflammation — when cAMP is high, the cell calms down; when it is low, the cell shouts out inflammatory signals. An enzyme called PDE4 constantly turns that knob down. Apremilast blocks PDE4, so the knob stays up: cAMP levels rise, and the immune cell dials back the chemicals that cause joint pain, skin plaques, and mouth ulcers.
In simple terms
Apremilast is a tablet that works inside immune cells. It blocks an enzyme called PDE4, which normally breaks down a molecule called cAMP. With PDE4 blocked, cAMP builds up and tells the immune cell to produce fewer inflammatory chemicals — including TNF-α, IL-23, and IL-17 — while increasing an anti-inflammatory signal called IL-10. The result is less joint swelling in psoriatic arthritis, thinner skin plaques in psoriasis, and fewer mouth ulcers in Behçet's disease. Apremilast is not a broad immunosuppressant and does not require routine blood monitoring for liver or kidney damage.
In depth
Apremilast is a selective inhibitor of phosphodiesterase 4 (PDE4), the predominant cAMP-phosphodiesterase in immune cells. By binding the catalytic site of PDE4 (primarily the PDE4B isoform in monocytes and T cells), apremilast prevents hydrolysis of cAMP to 5'-AMP, raising intracellular cAMP and activating protein kinase A (PKA). PKA phosphorylates and inhibits NF-κB and activates CREB, shifting the transcriptional programme away from pro-inflammatory cytokines (TNF-α, IL-12, IL-23, IFN-γ) and toward anti-inflammatory IL-10. In psoriatic arthritis and plaque psoriasis, this rebalancing reduces Th17/Th1-driven inflammation in skin and joints. In Behçet's disease, it dampens the innate immune over-activation that produces oral ulceration. Unlike biologics, apremilast does not deplete circulating lymphocytes or require laboratory monitoring for organ toxicity.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How apremilast dials back inflammation inside immune cells
- Inside immune cells, a molecule called cAMP acts like a volume knob on inflammation — when cAMP is high, the cell calms down; when it is low, the cell shouts out inflammatory signals.
- An enzyme called PDE4 constantly turns that knob down.
- Apremilast is a tablet that works inside immune cells.
- Apremilast blocks PDE4, so the knob stays up: cAMP levels rise, and the immune cell dials back the chemicals that cause joint pain, skin plaques, and mouth ulcers.
Target: Phosphodiesterase 4 (PDE4)
The main enzyme that breaks down cyclic AMP (cAMP) in immune cells; inhibiting PDE4 raises cAMP, which suppresses production of TNF-α, IL-23, IL-17, and IFN-γ while increasing the anti-inflammatory cytokine IL-10.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMA- Treatment of active psoriatic arthritis in adult patients who have had an inadequate response or who have been intolerant to a prior DMARD therapy, alone or in combination with DMARDs
- Treatment of moderate to severe chronic plaque psoriasis in adult patients who failed to respond to or who have a contraindication to, or are intolerant to, other systemic therapy including cyclosporine, methotrexate, or PUVA
- Treatment of moderate to severe plaque psoriasis in children and adolescents from 6 years of age and weighing at least 20 kg who are candidates for systemic therapy
- Treatment of adult patients with oral ulcers associated with Behçet's disease who are candidates for systemic therapy
Approved uses in United States
FDA- Active psoriatic arthritis in adults and paediatric patients 6 years of age and older weighing at least 20 kg
- Plaque psoriasis in adults who are candidates for phototherapy or systemic therapy; moderate to severe plaque psoriasis in paediatric patients 6 years of age and older weighing at least 20 kg who are candidates for phototherapy or systemic therapy
- Oral ulcers associated with Behçet's Disease in adults
Approved uses in United States
DailyMed- Active psoriatic arthritis in adults and paediatric patients 6 years of age and older weighing at least 20 kg
- Plaque psoriasis in adults who are candidates for phototherapy or systemic therapy; moderate to severe plaque psoriasis in paediatric patients 6 years of age and older weighing at least 20 kg
- Oral ulcers associated with Behçet's Disease in adults
Approved uses in United States
MedlinePlus- Psoriatic arthritis (a condition that causes joint pain and swelling and scales on the skin)
- Plaque psoriasis (skin disease in which red, scaly patches form on some areas of the body)
- Ulcers in the mouth in people with Behçet's syndrome (a disorder that causes blood vessel swelling in the body)
Approved uses in United States
NCI- An orally bioavailable small-molecule inhibitor of PDE4 that targets, binds to, and inhibits PDE4 activity, blocking cyclic AMP degradation and increasing intracellular cAMP levels; this decreases production of pro-inflammatory cytokines including TNF-alpha
Official sources
The statements on this page trace back to these records.
- Otezla (apremilast) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- U.S. Food and Drug Administration: OTEZLA prescribing information
U.S. Food and Drug Administration
- DailyMed: OTEZLA prescribing information
DailyMed, U.S. National Library of Medicine
- MedlinePlus: apremilast
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: apremilast
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.