Generic
Phenylephrine Hydrochloride
2 brands available in the market
At a glance
Phenylephrine Hydrochloride injection is used for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia. It is an α-1 adrenergic receptor agonist that increases systolic and diastolic blood pressures.
Description
Phenylephrine is an α-1 adrenergic receptor agonist. Following IV administration, increases in systolic and diastolic blood pressures, mean arterial pressure, and total peripheral vascular resistance are observed. The onset of blood pressure increase is rapid, typically within minutes. As blood pressure increases, vagal activity increases, resulting in reflex bradycardia.
Indications
- Clinically important hypotension resulting from vasodilation during anesthesia
Therapeutic class
Alpha adrenoceptor blocking drugs
Pharmacological class
α-1 Adrenergic Receptor Agonist
Pharmacology
Phenylephrine is an α-1 adrenergic receptor agonist that increases systolic and diastolic blood pressures, mean arterial pressure, and total peripheral vascular resistance following IV administration. Increased blood pressure leads to increased vagal activity, resulting in reflex bradycardia.
Mechanism of action
Increases blood pressure by activating α-1 adrenergic receptors, causing vasoconstriction.
Dosage
Adult Dose (Intravenous):
- Hypotension during anesthesia: Recommended initial dose 40-100 mcg IV bolus
- Additional boluses may be given every 1-2 minutes as needed; not to exceed 200 mcg in a single administration
Administration
- Administered by healthcare professional as IV injection
- Do not use if solution is colored or cloudy or contains particulate matter
- Discard any unused portion
Missed dose
If you miss a dose, consult your doctor.
Side effects
Side Effects:
- Reflex bradycardia
- Ischemia
- Hypertension
- Vomiting
- Nausea
- Neck pain
- Tremors
Precautions & warnings
- Exacerbation of Angina, Heart Failure, or Pulmonary Arterial Hypertension: May precipitate angina in patients with severe arteriosclerosis or history of angina; exacerbate underlying heart failure; increase pulmonary arterial pressure
- Bradycardia: Can cause severe bradycardia and decreased cardiac output
- Renal Toxicity: May increase need for renal replacement therapy in septic shock patients; monitor renal function
Contraindications
- Hypersensitivity to phenylephrine
Drug interactions
- MAOI, Oxytocin and oxytocic drugs, Tricyclic antidepressants, Atropine: Increased blood pressure effect
- α-adrenergic antagonists, mixed α and β receptor antagonists, Calcium channel blockers, Benzodiazepines: Decreased blood pressure effect
Food interactions
Not food-related (IV use).
Use in pregnancy
Use in Pregnancy: Data from randomized controlled trials and meta-analyses during cesarean section; no data on use during first or second trimester.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: No data on presence of phenylephrine or its metabolites in human or animal milk.
Pediatric use
Safety and efficacy not established in pediatric patients.
Geriatric use
Caution required in elderly patients (arteriosclerosis, cerebral/coronary circulation issues).
Renal / hepatic impairment
Renal Impairment: Risk of renal toxicity; monitor renal function.
Hepatic Impairment: Caution in liver disease; consult your doctor.
Overdose effects
Overdose: Rapid rise in blood pressure; symptoms include headache, vomiting, hypertension, reflex bradycardia, fullness in the head, tingling of extremities, and cardiac arrhythmias.
Storage conditions
Store below 30°C in a dry place, protected from light; keep out of reach of children.
Chemical structure
Phenylephrine Hydrochloride