快樂小藥師 Im pharmacist nichts glücklich

Guanabenz（Lisapres (BR);Rexitene (AT, IT);Tenelid (BR);Wytensin (AT,US)）

光看名字，就可以猜出大概跟將血壓有點關係，因為你的腦海中，可能會閃過這個藥物

Guanethidine

不過，他們兩個的機轉卻是不一樣的，比較起來，他跟Methyldopa反而比較相似。

 用途：

降血壓

機轉：

Stimulates alpha₂-adrenoreceptors in the brain stem, thus activating an inhibitory neuron, resulting in reduced sympathetic outflow, producing a decrease in vasomotor tone and heart rate

外觀：

用法：

成人： 

Hypertension: Oral: Initial: 4 mg twice daily; increase in increments of 4-8 mg/day every 1-2 weeks to a maximum of 32 mg twice daily.

 老人：Initial: 4 mg once daily, increase every 1-2 weeks（但並不是很建議用在65歲以上的老人身上）

比較需要注意的，應該是交互作用：

Amifostine: Antihypertensives may enhance the hypotensive effect of Amifostine. Management: When amifostine is used at chemotherapy doses, antihypertensive medications should be withheld for 24 hours prior to amifostine administration. If antihypertensive therapy can not be withheld, amifostine should not be administered. Risk D: Consider therapy modification

Antidepressants (Alpha2-Antagonist): May diminish the hypotensive effect of Alpha2-Agonists. Risk D: Consider therapy modification

Antihypertensives: May enhance the hypotensive effect of other Antihypertensives. Risk C: Monitor therapy

Beta-Blockers: May enhance the rebound hypertensive effect of Alpha2-Agonists. This effect can occur when the alpha₂-agonist is abruptly withdrawn. Exceptions: Levobunolol; Metipranolol. Risk D: Consider therapy modification

CYP1A2 Inducers (Strong): May increase the metabolism of CYP1A2 Substrates. Risk C: Monitor therapy

CYP1A2 Inhibitors (Moderate): May decrease the metabolism of CYP1A2 Substrates. Risk C: Monitor therapy

CYP1A2 Inhibitors (Strong): May decrease the metabolism of CYP1A2 Substrates. Risk D: Consider therapy modification

Diazoxide: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy

Herbs (Hypertensive Properties): May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy

Herbs (Hypotensive Properties): May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy

Hypotensive Agents: May enhance the adverse/toxic effect of other Hypotensive Agents. Risk C: Monitor therapy

Iobenguane I 123: Alpha2-Agonists may diminish the therapeutic effect of Iobenguane I 123. Risk X: Avoid combination

MAO Inhibitors: May enhance the orthostatic effect of Orthostasis Producing Agents. Risk C: Monitor therapy

Methylphenidate: May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy

Pentoxifylline: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy

Phosphodiesterase 5 Inhibitors: May enhance the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy

Prostacyclin Analogues: May enhance the hypotensive effect of Antihypertensives. Risk C: Monitor therapy

RiTUXimab: Antihypertensives may enhance the hypotensive effect of RiTUXimab. Risk D: Consider therapy modification

Serotonin/Norepinephrine Reuptake Inhibitors: May diminish the antihypertensive effect of Alpha2-Agonists. Risk C: Monitor therapy

Tricyclic Antidepressants: May diminish the antihypertensive effect of Alpha2-Agonists. Risk D: Consider therapy modification

Yohimbine: May diminish the antihypertensive effect of Antihypertensives. Risk C: Monitor therapy

懷孕分級：C

Pharmacodynamics/Kinetics

Onset of action: Antihypertensive: ~1 hour

Absorption: ~75%

Half-life elimination, serum: 7-10 hours

 劑型上面沒有特殊設計，要切要磨都可以。