“Fight or flight” effects including ↑ BP, CNS arousal, pupillary dilation and ↓ digestive activity
➔ stimulant-like sympathomimetic effects
➔ reflex bradycardia
Hypertension, agitation, or seizures with excessive sympathomimetic stimulation
➔ rebound congestion (rhinitis medicamentosa) with prolonged use
Appetite suppression
Urinary retention
Alpha-1 agonist (2/2)
The opposite effect of prazosin
Drugs with this mechanism (13)
Clonidine — Central alpha-2 agonist for hypertension, ADHD and withdrawal; sedation and rebound.
Clonidine ER — Extended-release central alpha-2 agonist for ADHD; sedation and rebound hypertension limit it.
Desglymidodrine — Active midodrine metabolite that stimulates peripheral alpha-1 receptors; raises standing blood pressure but can cause supine hypertension.
Dihydro ergotamine — Injectable or intranasal ergot for refractory migraine; never combine closely with a triptan.
Dobutamine — Beta-1 inotrope; titratable within minutes.
Dopamine — Dose-sensitive endogenous catecholamine agonist used IV for selected shock and hypotension.
Epinephrine — Endogenous catecholamine; the first-line drug for anaphylaxis and arrest.
Ergotamine — Ergot alkaloid for migraine; vasoconstrictive, largely supplanted by triptans.
Methylergonovine — Ergot uterotonic for postpartum hemorrhage; contraindicated in hypertension.
Norepinephrine — Endogenous catecholamine; the first-line vasopressor for shock.
Clonidine ER suspension — Extended-release clonidine liquid for ADHD; sedation and rebound hypertension shape use.
Oxymetazoline — Topical alpha agonist decongestant; rebound congestion with overuse.
Phenylephrine — Alpha-1 agonist vasopressor and topical decongestant; oral congestion products are ineffective.