See the full prescribing information for recommended evaluations and immunizations prior to treatment. Administer ILUMYA by subcutaneous injection. Recommended dosage: Moderate-to-Severe Plaque Psoriasis 100 mg at Weeks 0, 4, and every 12 weeks thereafter. Active Psoriatic Arthritis For adult patients with active psoriatic arthritis and coexistent moderate-to-severe plaque psoriasis, the recommended dosage is the same as in adults with moderate-to-severe plaque psoriasis. For other adult patients with active psoriatic arthritis: 100 mg every 12 weeks.