Alpha Blockers: Phenoxybenzamine, Phentolamine, Prazosin, Terazosin, Doxazosin, Labetalol mnemonic

Alpha Blockers [Top of adrenergic clover]

Alpha 1 & 2 blockers
- Phenoxybenzamine [Fan ox Mercedes-Benz mine]
  - Irreversibly damages alpha-1 and alpha-2 receptors [Tires rip clover surface]
  - Alpha-1 receptors normally vasoconstrict, so damaging this receptor results in vasodilation [dilated vase on mine]
  - Lowers blood pressure, resulting in reflex tachycardia [heart running away from underneath the tire]
- Phentolamine [Fan tall mine]
  - Competitively inhibits alpha-1 and alpha-2 receptors [Gently blows away norepinephrine/epinephrine [red rhino]]
  - Lowers blood pressure, resulting in reflex tachycardia [heart running with the wind, low BP indicators]
  - Used in diagnosis of pheochromocytoma [tumor in adrenal gland medulla]
Selective competitive alpha-1 blockers
- Names end in -zosin [Zoo sin] [Forbidden apple tree (original sin) growing in a zoo blocks rhino from reaching alpha-1 receptor. Blocking does not damage the receptor, and so it's a competitive block]
- Prazosin [bra zoo sin]
- Terazosin [terra zoo sin (terra=earth)]
- Doxazosin [dog's zoo sin]
- Useful in lowering blood pressure [pulling on the apple also pulls lower the level of BP indicator]
- Relax smooth muscle in enlarged prostate and so improve urine flow [copious urine despite big prostate]
Labetalol inhibits alpha-1 as well as beta-1 [Label lollipop stuck on both alpha-1 and beta-1 portions of adrenergic clover]
Adverse effects of alpha-1 blockers include
- dizziness [spinning halo]
- impotence
- tachycardia
- orthostatic hypotension [only bloody shoes & ankles when standing up]

Visual Mnemonic - Alpha Blockers: Phenoxybenzamine, Phentolamine, Prazosin, Terazosin, Doxazosin, Labetalol