When should a beta-adrenergic receptor blocker be considered contraindicated?

A beta-adrenergic receptor blocker should be considered contraindicated in the context of suspected pheochromocytoma due to the potential for exacerbating severe hypertension. Pheochromocytoma is a tumor of the adrenal gland that secretes excess catecholamines, which can lead to episodes of hypertension. When a beta-blocker is administered without prior alpha-blockade, it can cause unopposed alpha-adrenergic receptor activity due to the blocking of beta receptors. This means that while the beta receptors affecting the heart rate and vasodilation are blocked, the alpha receptors that cause vasoconstriction may still be activated, leading to a dangerous increase in blood pressure.

In managing asthma, the concern arises from the use of non-selective beta-blockers potentially triggering bronchospasm; however, selective beta-2 agonists are available to mitigate this risk. Older adults may require cautious use of beta-blockers due to the potential for adverse effects, but they are not universally contraindicated. The administration of narcotics does not inherently contraindicate the use of beta-blockers, though opioids may affect respiratory function and blood pressure, requiring careful monitoring. Therefore, the specific context of pheochromocytoma is critical when considering beta-block