Alpha-2-agonists (central acting)

Should be used cautiously in older patients because of orthostatic hypotension

Interferes with measurements of urinary catecholamine levels by fluorometric methods

Should not be combined with an alpha-1-blocker because of a risk of significant orthostatic hypotension.

Guanabenz

Alpha-1-blockers

First-dose syncope, orthostatic hypotension, weakness, palpitations, headache

Should be used cautiously in older patients because of orthostatic hypotension

Relieves symptoms of benign prostatic hyperplasia