Patients on immunosuppressive therapy have an increased risk of infections. Since infections have a potential to trigger acute porphyric attacks vigilance is motivated regarding signs or symptoms of infection and/or possible symptoms of a porphyric attack. Side effects like nausea and vomiting may potentially be porphyrinogenic through reduction in carbohydrate intake.

Infections are common in patients using immunosuppressants and since infections might trigger an acute porphyric attack, vigilance regarding signs and symptoms of an infection and/ or a porphyric attack is recommended. Common adverse reactions of ustekinumab that can be confused with an acute porphyric attack are nausea and vomiting. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

Antibody preparation with no CYP metabolism. Based on the pharmacokinetics, ustekinumab is not expected to have any porphyrinogenic effects.

Ustekinumab is a fully human IgG1-kappa monoclonal antibody against interleukin 12 and 23 produced in a murine myeloma cell line using recombinant DNA technology.

Ustekinumab is used in the treatment of moderate to severe plaque psoriasis. It is administered as an subcutaneus injection.

The metabolism of ustekinumab is expected to be similar as for endogenous antibodies, which are metabolised to peptides and amino acids in various body tissues and in plasma by circulating phagocytic cells or by their target antigen-containing cells. Immunosuppressive treatment can reverse the down-regulation of the expression of CYP enzymes (CYP 3A4, 1A2, 2C9 or 2C19) caused by inflammatory cytokines. This effect is not suspected to be porphyrinogenic as the CYP enzyme activity is not induced above a normal level.