Phenylephrine Hydrochloride

Phenylephrine Hydrochloride injection is indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia.

Phenylephrine is an α-1 adrenergic receptor agonist. Following Phenylephrine intravenous administration, increases in systolic and diastolic blood pressures and arterial blood pressure are observed. The onset of blood pressure increase is rapid, typically within minutes.

Following phenylephrine hydrochloride intravenous administration, increases in systolic and diastolic blood pressures, mean arterial blood pressure, and total peripheral vascular resistance are observed. The onset of blood pressure increase following an intravenous bolus phenylephrine hydrochloride administration is rapid, typically within minutes. As blood pressure increases following intravenous administration, vagal activity also increases, resulting in reflex bradycardia. Phenylephrine has activity on most vascular beds, including renal, pulmonary, and splanchnic arteries.

Dosing for treatment of hypotension during anesthesia: The recommended initial dose is 40 to 100 mcg administered by intravenous bolus. Additional boluses may be administered every 1-2 minutes as needed; not to exceed a total dosage of 200 mcg in a single administration. Do not use if the solution is colored or cloudy or if it contains particulate matter. Discard any unused portion.

The increasing blood pressure effect of Phenylephrine is increased in patients receivingMonoamine oxidase inhibitors (MAOI), Oxytocin and oxytocic drugs, Tricyclic antidepressants & Atropine. The increasing blood pressure effect of Phenylephrine is decreased in patients receiving- α-adrenergic antagonists, mixed α and β receptor antagonists, Calcium channel blockers & Benzodiazepines.

Adverse reactions to Phenylephrine are primarily attributable to excessive pharmacologic activity. Adverse reactions reported in published clinical studies, observational trials, and case reports of Phenylephrine are reflex bradycardia, ischemia, hypertension, vomiting, nausea, neck pain & tremors by body system.

Data from randomized controlled trials and meta-analyses with Phenylephrine injection use in pregnant women during caesarean section have not established a drug-associated risk of major birth defects and miscarriage. There are no data on the use of Phenylephrine during the first or second trimester. There are no data on the presence of Phenylephrine injection or its metabolite in human or animal milk, the effects on the breastfed infant, or the effects on milk production.

Exacerbation of Angina, Heart Failure, or Pulmonary Arterial Hypertension: Because of its increasing blood pressure effects, Phenylephrine can precipitate angina in patients with severe arteriosclerosis or history of angina, exacerbate underlying heart failure, and increase pulmonary arterial pressure.

Bradycardia: Phenylephrine can cause severe bradycardia and decreased cardiac output.

Renal Toxicity: Phenylephrine can increase the need for renal replacement therapy in patients with septic shock. Monitor renal function.

Overdose of Phenylephrine can cause a rapid rise in blood pressure. Symptoms of overdose include headache, vomiting, hypertension, reflex bradycardia, a sensation of fullness in the head, tingling of the extremities, and cardiac arrhythmias.

Alpha adrenoceptor blocking drugs

Store at below 30°C in a dry place protected from light. Keep out of reach of Children.