Brodalumab, sold under the brand name Siliq, is an injectable biologic medication used to treat moderate-to-severe plaque psoriasis in adults who may need systemic therapy or phototherapy. It works by blocking the interleukin-17 receptor, which helps reduce the inflammatory signals that drive psoriasis. Brodalumab may be a good option for people with widespread, severe, or stubborn psoriasis that has not improved enough with topical treatments, light therapy, or other systemic medications. It is given as a subcutaneous injection, with starter doses followed by maintenance dosing every 2 weeks. Because it affects the immune system, clinicians usually screen for infections such as tuberculosis before starting treatment. Possible side effects include joint pain, headache, fatigue, diarrhea, fungal infections, injection-site reactions, and increased risk of infection; it also has a boxed warning for suicidal thoughts and behavior, so mood history should be discussed before starting.