Master Psoriasis Pharmacology with Picmonic for Medicine

Methotrexate is a folate antimetabolite that competitively inhibits dihydrofolate reductase, reducing DNA synthesis. It also has anti-inflammatory effects through increased adenosine signaling. Methotrexate is used in moderate to severe psoriasis or when topical therapies fail.

Topical agents used to treat psoriasis are corticosteroids, tacrolimus, tazarotene, and vitamin D analogs. It is effective in mild to moderate psoriasis, with less than 5% of the body surface affected, sparing the genitals, hands, feet, and face.

TNF-α is a proinflammatory cytokine involved in the pathogenesis of psoriasis. Inhibiting TNF-α helps treat moderate to severe psoriasis, defined as affecting >5% of body surface area or involving the hands, feet, face, or genitals. Infliximab is a TNF-α inhibitor that binds both soluble and transmembrane TNF-α and provides one of the most rapid clinical responses among biologic therapies.

Adalimumab is another example of a TNF-α inhibitor that targets soluble TNF-α. Patients should also be screened for TB, the PPD tuberculin test due to the risk of TB reactivation. This is also indicated in patients using infliximab.

Etanercept acts by blocking the interaction between TNF and its receptor. It can be used as a treatment option to treat moderate to severe psoriasis.

The IL-23/IL-17 axis is currently thought to be involved in the principal pathogenic pathway in psoriasis. Guselkumab is the first drug in its class, an IL-23 blocker, to be approved by the FDA as a treatment option for moderate-severe plaque psoriasis.

Bimekizumab is an inhibitor of interleukin 17A and 17F, and refers to immuinoglobulin monoclonal antibody used to treat moderate and severe plaque psoriasis.

Psoriasis patients are found to respond to treatment that interferes with lymphocyte activation, the tumor necrosis factor (TNF) pathway, agents blocking interleukin (IL)-17, or the IL-12/23p40 subunit.
Ustekinumab is a fully human immunoglobulin G1κ (IgG1κ) monoclonal antibody that targets the p40 subunit shared by IL-12 and IL-23.

Ixekizumab is an IL-17A antagonist used to treat moderate to severe plaque psoriasis. It should be avoided in patients with inflammatory bowel disease.

Secukinumab is an IL-17A antagonist used to treat moderate to severe plaque psoriasis.