ADMINISTRATION ROUTES:
IV
ALTERNATIVE NAMES:
Neosynephrine
ICU INDICATIONS:
- Hypotension
PRESENTATION AND ADMINISTRATION:
IV:
10 mg in 1 mL (10%) solution
Add 10 mg to 100 mL of compatible IV fluid to give concentration of 100 mcg/mL and administer by infusion.
Compatible with the following IV fluids: Normal saline, 5% glucose, Glucose and sodium chloride, Hartmanns
Discard any solution not used within 24 hours of preparation. Store at room temperature
DOSAGE:
IV:
Bolus:
100 - 500 mcg (1 - 5 mL) PRN
Infusion:
1 - 50 mL/hr
If higher infusion doses are required, consider switching to noradrenaline
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose as in normal renal function
DOSAGE IN PAEDIATRICS:
IV:
Bolus:
2 - 10 mcg/kg
Infusion:
1 - 5 mcg/kg/min
CLINICAL PHARMACOLOGY:
Phenylephrine hydrochloride is a powerful postsynaptic alpha-receptor stimulant with little effect on the beta-receptors of the heart. The predominant actions of phenylephrine hydrochloride are on the cardiovascular system. Cardiac output is decreased due to a combination of a decrease in both heart rate and stroke volume. As such, phenylephrine is a negative inotrope. Although it increases cerebral blood flow, it decreases cerebral tissue oxygen saturation.
CONTRAINDICATIONS:
- Hypotension solely due to low cardiac output
- Hypersensitivity to phenylephrine
WARNINGS:
Contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.
PRECAUTIONS:
General:
Phenylephrine hydrochloride should be used with caution in elderly patients or in patients with hyperthyroidism, bradycardia, partial heart block, myocardial disease, or severe arteriosclerosis.
Laboratory Tests:
No tests in addition to routine ICU tests are indicated
Drug/Laboratory Test Interactions:
None noted
IMPORTANT DRUG INTERACTIONS IN ICU:
Monoamine oxidase inhibitors
Phenylephrine may have a prolonged or exaggerated effect in the presence of MAOIs which inhibit its metabolism. This may occur several weeks after stopping MAOIs.
ADVERSE REACTIONS:
Cardiovascular:
Arrhythmia (rare), decreased cardiac output, hypertension, pallor, precordial pain or discomfort, reflex bradycardia, severe peripheral and visceral vasoconstriction
Central nervous system:
Anxiety, dizziness, excitability, giddiness, headache, insomnia, nervousness, restlessness
Endocrine & metabolic:
Metabolic acidosis
Gastrointestinal:
Gastric irritation, nausea
Neuromuscular & skeletal:
Paraesthesia, pilomotor response, tremor, weakness
Renal:
Decreased renal perfusion, reduced urine output
Respiratory:
Respiratory distress
Miscellaneous:
Hypersensitivity reactions (including rash, urticaria, leukopaenia, agranulocytosis, thrombocytopaenia)