フェニレフリン

使用用途

• To increase blood pressure by vasoconstriction in pronounced systemic vasodilation or when increasing myocardial contractility is disadvantageous (e.g., hypertrophic cardiomyopathy)
• As a constant rate infusion for profound vasodilation due to septic shock
• As a vasopressor in catastrophic stages of hypovolemic shock
• As a CRI to increase peripheral vascular resistance and mean arterial blood pressure
• Diagnosis of Horner's syndrome (denervation hypersensitivity)
• General use
• As a CRI to increase peripheral vascular resistance and mean arterial blood pressure
• As a constant rate infusion for profound vasodilation due to septic shock
• As a vasopressor in catastrophic stages of hypovolemic shock
• Diagnosis of Horner's syndrome (denervation hypersensitivity)
• Hypotension secondary to drugs or vascular failure

投与方法

考えられる副作用

• Reflex bradycardia
• CNS effects (excitement, restlessness, headache)
• Arrhythmias (rare)
• Severe extravasation injuries (tissue necrosis and sloughing)
• Hypertension
• Tachycardia
• Tissue necrosis and sloughing (if IV extravasation occurs)

注意事項と禁忌

• Severe hypertension
• Ventricular tachycardia
• Hypersensitivity to phenylephrine
• Do not apply topically once ophthalmic surgery has started (to avoid direct arterial absorption)
• > **WARNING**: Extravasation injuries with phenylephrine can be very serious, leading to necrosis and sloughing of surrounding tissue. IV sites must be routinely monitored. If extravasation occurs, infiltrate the ischemic area with 5-10 mg phentolamine in 10-15 mL of normal saline using a fine needle. - **Extreme Caution**: Use carefully in geriatric patients, and those with hyperthyroidism, bradycardia, partial heart block, or other heart disease. - **Not a Substitute for Fluids**: Phenylephrine is not a replacement for adequate volume therapy in patients with shock; hypovolemia must be corrected first. - **Pregnancy**: FDA Category C. Can cause contraction of the pregnant uterus and constriction of uterine blood vessels. Use with caution.

薬物相互作用

• Alpha-Adrenergic Blockers (phentolamine, phenothiazines, phenoxybenzamine): Higher dosages of phenylephrine may be required to attain a pressor effect if these agents have been used prior to therapy.
• Anesthetics, General (halogenated): Potentially may induce cardiac arrhythmias when used with halothane anesthesia.
• Atropine (and other anticholinergics): Block the reflex bradycardia caused by phenylephrine.
• Beta-Adrenergic Blockers: The cardiostimulatory effects of phenylephrine (seen at high doses) can be blocked.
• Digoxin: Use with phenylephrine may cause increased myocardium sensitization.
• Monoamine Oxidase (MAO) Inhibitors (e.g., amitraz, selegiline): Should not be used with phenylephrine because of a pronounced pressor effect.
• Oxytocin: When used concurrently with oxytocic agents, pressor effects may be enhanced.
• Sympathomimetic Agents (epinephrine): Tachycardia and serious arrhythmias are possible.
• Volatile anaesthetic agents: Increased risk of cardiac arrhythmias
• Oxytocic agents: Enhanced pressor effects leading to severe hypertension

よくある質問