Question

Why adrenaline is contraindicated in hyperthyroidism?

Answer 1

The patient suffering from thyroid dysfunction can be a euthyroid (thyroid function under control), hyperthyroid (excess secretion of thyroid hormones) and hypothyroid (less secretion of thyroid hormone). The main concern about use of adrenaline in thyroid patients is in hyperthyroid patients. In hyperthyroid patients use if adrenaline can cause increase in heart rate (tachycardia), irregular heart beats (arrhythmia) and high blood pressure followed by cardiac arrest. This is due to the vacoconstrictor effexct of adrenaline. Hypothyroid patients have slow metabolic rate, so it is important to take care that excess of drugs are not administered or else it may cause systemic toxicity. Patients with euthyroid state do not face these problems. Local anesthetics solution mainly contain the main local anesthetic salt aong with adrenaline in various quantities and many other ingredients. The adrenaline added in local anesthetics has is advantages like less loss of blood, increased depth of LA, along with increased duration or effectiveness of LA. So use of LA in thyroid patients will have the same effect as use of adrenaline in these patients. To overcome this problem, use of plain LA i.e. Without adrenaline, can be used in such patients as a precautionary measure.