Blue-grey hyperpigmentation in acne after vandetanib therapy and doxycycline use: A case report

Vandetanib is an oral tyrosine kinase inhibitor with cutaneous adverse effects that include the development of acne. We present a patient who underwent vandetanib therapy for stage IV medullary thyroid cancer in conjunction with the use of doxycycline for acne that developed. After vandetanib use, blue-grey pigmentation developed in the acne on his face, chest, back, and arms, which darkened after the use of doxycycline. We review the literature to report that this blue-grey hyperpigmentation was likely vandetanib-induced but may have been the result of both drugs being used in combination.

Therapeutic drug monitoring for biological medications in inflammatory bowel disease

Therapeutic drug monitoring (TDM) is the measurement of serum drug concentrations and anti-drug-antibodies (ADA) for biologic therapies used to treat inflammatory bowel disease (IBD). The aim of this article is to review the current literature concerning reactive and proactive TDM for both adults and children with IBD. Although optimal trough concentration windows for some of these medications are not well defined, there is mounting evidence to suggest that reactive TDM is associated with favorable therapeutic outcomes, including less immunogenicity, greater drug exposure, and a decreased risk of treatment failure. Moreover, while the exact mechanism of loss of response is not fully elucidated, the vast majority of studies have reported a decreased incidence of nonresponse and secondary loss of response when TDM is implemented. Proactive TDM, while even less understood in the literature, employs a schedule of preemptive analysis of serum trough concentrations to accordingly adjust the patient's biologic dosage. Proactive TDM may decrease the need for IBD-related surgery/hospitalization, and therefore merits future studies of investigation.