Fenilefrina
Phenylephrine
Phenylephrine Hydrochloride
También conocido como: Neo-Synephrine · AH-chew D · Little Colds Decongestant · Lusonal · Nasop · Sudogest PE · Sudafed PE · Pedia Care Children's Decongestant · Triaminic Thin Strips Cold · Minims Phenylephrine · fenilefrina · phenylephrinum · m-synephrine · Phenylephrine hydrochloride
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Dosis por especie
🌎 NA — North America🌍 EU — Europe
Perros
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| As a CRI to increase peripheral vascular resistance and mean arterial blood pressure | Low dose is 1 microgram/kg/min; high dose is 3 micrograms/kg/min | IV | CRI | — | 🌎 NA |
| As a constant rate infusion for profound vasodilation due to septic shock | 2-10 micrograms/kg/minute | IV | CRI | — | 🌎 NA |
| As a vasopressor in catastrophic stages of hypovolemic shock | 1-3 micrograms/kg/min | IV | CRI | — | 🌎 NA |
| Diagnosis of Horner's syndrome (denervation hypersensitivity) | 1% or 10% solution topically to both eyes | topical | once | single dose | 🌍 EU |
| Hypotension secondary to drugs or vascular failure | Used in conjunction with fluid therapy (exact dose not specified in monograph) | IV | CRI or as directed | Until blood pressure stabilizes | 🌍 EU |
- As a CRI to increase peripheral vascular resistance and mean arterial blood pressure: May see reflex bradycardia, and vasoconstriction can lead to excessive decreases in blood flow to liver, GI tract, and kidneys, although coronary blood flow is increased.
- Diagnosis of Horner's syndrome (denervation hypersensitivity): Time to dilation indicates lesion location: <20 mins = 3rd-order HS; 20-45 mins = 2nd-order HS; 60-90 mins = 1st-order HS or normal. 10% solution causes mydriasis in 5-8 mins in post-ganglionic lesions.
- Hypotension secondary to drugs or vascular failure: Use with caution; raises BP at the expense of vital organ perfusion.
Gatos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| To increase blood pressure by vasoconstriction in pronounced systemic vasodilation or when increasing myocardial contractility is disadvantageous (e.g., hypertrophic cardiomyopathy) | 1-2 micrograms/kg/minute | IV | CRI | — | 🌎 NA |
| As a constant rate infusion for profound vasodilation due to septic shock | 2-10 micrograms/kg/minute | IV | CRI | — | 🌎 NA |
| As a vasopressor in catastrophic stages of hypovolemic shock | 1-3 micrograms/kg/min | IV | CRI | — | 🌎 NA |
| As a CRI to increase peripheral vascular resistance and mean arterial blood pressure | Low dose is 1 microgram/kg/min; high dose is 3 micrograms/kg/min | IV | CRI | — | 🌎 NA |
| Diagnosis of Horner's syndrome (denervation hypersensitivity) | 1% solution topically to both eyes | topical | once | single dose | 🌍 EU |
- To increase blood pressure by vasoconstriction in pronounced systemic vasodilation or when increasing myocardial contractility is disadvantageous (e.g., hypertrophic cardiomyopathy): Infusions of 1 microgram/kg/min significantly increased mean arterial pressure without a change in cardiac output. At 2 micrograms/kg/min, cardiac index also was increased with an increase in stroke volume index.
- As a CRI to increase peripheral vascular resistance and mean arterial blood pressure: May see reflex bradycardia, and vasoconstriction can lead to excessive decreases in blood flow to liver, GI tract, and kidneys, although coronary blood flow is increased.
- Diagnosis of Horner's syndrome (denervation hypersensitivity): Use lower concentrate solutions in cats to avoid systemic hypertension.
Caballos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| General use | 5 mg | IV | Single dose | — | 🌎 NA |
- General use: ARCI UCGFS Class 3 Drug
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La fenilefrina es una amina simpaticomimética sintética de acción directa y potente, utilizada principalmente en medicina veterinaria por sus profundas propiedades vasoconstrictoras.
Las aplicaciones clínicas clave incluyen:
- Hipotensión y shock: Se utiliza por vía parenteral para elevar la presión arterial (tras una reposición adecuada de volumen) sin causar una estimulación cardíaca excesiva.
- Hipotensión inducida por fármacos: Altamente eficaz para crisis hipotensivas secundarias a sobredosis de fármacos o reacciones idiosincrásicas (p. ej., fenotiazinas, agentes bloqueadores adrenérgicos).
- Uso oftálmico: Se aplica tópicamente para exámenes diagnósticos oculares, reduciendo la formación de sinequias posteriores y aliviando el dolor asociado con la uveítis complicada.
- Descongestión nasal: Se aplica por vía intranasal para reducir la congestión de la mucosa.
Perla clínica: Debido a que la fenilefrina carece de actividad beta-adrenérgica significativa a dosis normales, es particularmente útil cuando se necesita un aumento de la presión arterial pero está contraindicado un aumento de la frecuencia cardíaca o del trabajo miocárdico (p. ej., en pacientes con miocardiopatía hipertrófica).
Mecanismo de acción
Phenylephrine is a highly selective alpha-1 adrenergic receptor agonist.
- Vascular Smooth Muscle: Binds to post-synaptic alpha-1 receptors → activates Gq-proteins → stimulates Phospholipase C (PLC) → cleaves PIP2 into Inositol Triphosphate (IP3) and Diacylglycerol (DAG) → IP3 triggers the release of intracellular calcium from the sarcoplasmic reticulum → profound vasoconstriction.
- Cardiovascular Effects: Intravenous administration causes peripheral vasoconstriction, leading to significant increases in both diastolic and systolic blood pressures. This sudden increase in blood pressure often triggers a baroreceptor-mediated reflex bradycardia (which can be blocked by anticholinergics like atropine).
- Organ Perfusion: Constricts most vascular beds (renal, splanchnic, pulmonary, cutaneous), though coronary blood flow is typically increased due to elevated aortic diastolic pressure.
Seguridad y advertencias
Contraindicaciones
- Severe hypertension
- Ventricular tachycardia
- Hypersensitivity to phenylephrine
- Do not apply topically once ophthalmic surgery has started (to avoid direct arterial absorption)
Efectos adversos
- 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)
Precauciones
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.
Interacciones farmacológicas
Higher dosages of phenylephrine may be required to attain a pressor effect if these agents have been used prior to therapy.
Potentially may induce cardiac arrhythmias when used with halothane anesthesia.
Block the reflex bradycardia caused by phenylephrine.
The cardiostimulatory effects of phenylephrine (seen at high doses) can be blocked.
Use with phenylephrine may cause increased myocardium sensitization.
Should not be used with phenylephrine because of a pronounced pressor effect.
When used concurrently with oxytocic agents, pressor effects may be enhanced.
Tachycardia and serious arrhythmias are possible.
Increased risk of cardiac arrhythmias
Enhanced pressor effects leading to severe hypertension
Monitorización
- Cardiac rate and rhythm
- Blood gases (if possible)
- IV catheter site (for signs of extravasation)
- Blood pressure (systemic use or high-concentration topical use)
- Heart rate and rhythm (ECG)
- Pupillary response and time to dilation (for Horner's syndrome testing)
Farmacocinética
Vida media
Absorción
After oral administration, phenylephrine is rapidly metabolized in the GI tract and cardiovascular effects are generally unattainable via this route. Following IV administration, pressor effects begin almost immediately and persist for up to 20 minutes. IM onset is 10-15 minutes, lasting approximately one hour.
Distribución
It is unknown if phenylephrine is excreted into milk.
Metabolismo
Metabolized by the liver.
Eliminación
The effects of the drug are terminated by uptake into tissues.
Sobredosis
The margin of safety with phenylephrine overdose is fairly wide, especially after oral administration.
Clinical Signs:
- Common findings in dogs include vomiting, lethargy, depression, hyperactivity, and tachycardia.
- Severe overdosage can cause hypertension, seizures, paresthesias, ventricular extrasystoles, and cerebral hemorrhage.
Treatment:
- Vomiting is commonly seen and may self-decontaminate oral exposures.
- Cardiovascular changes often respond well to IV fluids.
- Beta-blockers or nitroprusside may be indicated when signs (tachycardia, severe hypertension) are refractory to fluids.
Productos disponibles
Formulaciones
- Injection
- Oral tablets
- Oral solution/liquid
- Oral strips
- Ophthalmic drops
- Intranasal sprays
- Injectable: 1% (10 mg/ml) solution
- Ophthalmic: 2.5% solution (single-dose vials)
- Ophthalmic: 10% solution (single-dose vials)
Veterinario
- Oral combination products marketed as 'cough' syrups containing phenylephrine, pyrilamine, guaifenesin, sodium citrate, and sometimes ammonium chloride.
- Phenylephrine 1% injectable solution
- Phenylephrine 2.5% ophthalmic solution
- Phenylephrine 10% ophthalmic solution
Etiquetado para humanos
- Phenylephrine HCl Oral Tablets: 10 mg (regular & chewable)
- Phenylephrine HCl Oral Solution/Liquid: 2.5 mg/mL (concentrate), 2.5 mg/5mL & 7.5 mg/5 mL
- Phenylephrine HCl Oral Strips: 2.5 mg
- Phenylephrine HCl Injection: 1% (10 mg/mL) in 1 mL & 5 mL vials and 1 mL Uni-Nest amps
- Ophthalmic and intranasal dosage forms
- Minims Phenylephrine Hydrochloride 2.5% and 10% eye drops
Estado regulador
POM (Prescription Only Medicine)
POM-V or POM depending on specific formulation.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
The injectable product should be stored protected from light. Do not use solutions if they are brown or contain a precipitate. Oxidation of the drug can occur without a color change. Commercially available ampules have air replaced with nitrogen and a sulfite added to protect against oxidation.
Información para el cliente
- Uso hospitalario: La fenilefrina inyectable es un fármaco cardiovascular potente que solo debe ser utilizado por profesionales veterinarios en un entorno clínico donde se disponga de monitorización continua de la presión arterial y ECG.
- Productos orales: Los medicamentos para el resfriado de venta libre para humanos que contienen fenilefrina nunca deben administrarse a mascotas sin instrucciones veterinarias explícitas, ya que a menudo contienen otros ingredientes tóxicos (como paracetamol o descongestionantes) y pueden causar vómitos, hiperactividad o cambios en la frecuencia cardíaca.
- Ingestión accidental: Si su mascota ingiere accidentalmente un producto que contiene fenilefrina, comuníquese con su veterinario o con un centro de control de envenenamiento animal de inmediato.
La referencia de medicamentos de VetSheet está destinada a profesionales veterinarios autorizados como ayuda para la toma de decisiones clínicas, no como sustituto del criterio profesional ni del prospecto actual del fabricante.