Adrenergic agonists adverse effects

This chapter will review the characteristics and regulatory properties of a2 receptors, neuropharmacology of the a2-adrenergic agonists, hypothesized mechanisms by which these medications alter central nervous system (CNS) activity, as well as a variety of issues related to their clinical use, including safety and adverse effects, dosing, and medication interactions. 

Some adverse effects observed with adrenergic agonists. 

Cardiovascular Disease. Patients with systemic hypertension, arteriosclerosis, and other cardiovascular diseases may be at risk when high concentrations of topically administered adrenergic agonists such as phenylephrine are used. Repeated topical doses or soaked cotton pledgets placed in the conjunctival sac have been associated with adverse cardiovascular effects. Likewise, P-blockers should be avoided or used cautiously in patients with congestive heart disease, severe bradycardia, and high-grade atrioventricular block. Topical P-blockers, however, may be used safely in patients with cardiac pacemakers. 

Thyroid Disease. Elevated blood pressure or other adverse cardiovascular effects can result when patients with Graves disease receive adrenergic agonists with vasopressor activity. This is due to the increased catecholamine activity associated with hyperthyroidism. The primary agent to be avoided or used cautiously is topically applied phenylephrine for pupillary dilation. 

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