The programmed death 1 (PD-1) inhibitors (eg, nivolumab and pembrolizumab) and the combination of a cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4; eg, ipilimumab) with a PD-1 inhibitor cause a destructive thyroiditis in which hyperthyroidism may more rapidly transition to hypothyroidism than with other causes of destructive thyroiditis [38].