Which vasoconstrictor is contraindicated (or should be used with the most caution) in a patient with hyperthyroidism?

Patients with uncontrolled or poorly controlled hyperthyroidism have an exaggerated sensitivity to circulating catecholamines, and dental local anesthesia textbooks specifically caution against (or limit) the use of epinephrine-containing local anesthetics in this population due to the risk of triggering a thyrotoxic/cardiovascular crisis. (Amitriptyline isn't itself a vasoconstrictor — it's a tricyclic antidepressant whose interaction concern with vasoconstrictors is a separate topic.)