Phenylephrine parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Injections of phenylephrine.
Drugs List
Therapeutic Indications
Uses
Hypotension - acute
Treatment of hypotension during epidural, spinal and general anaesthesia.
Unlicensed Uses
Priapism
Dosage
Adults
10mg/ml solution
Subcutaneous or intramuscular injection
2mg to 5mg with further doses of 1mg to 10mg if necessary, depending on response.
Slow intravenous injection
100micrograms to 500micrograms as a 0.1% solution repeated as necessary after at least 15 minutes.
Intravenous infusion
10mg in 500ml of glucose 5% injection or sodium chloride 0.9% injection at a rate of up to 180micrograms/minute, reduced to 30micrograms/minute to 60micrograms/minute according to response.
100micrograms/ml solution
Intravenous bolus injection
50micrograms to 100micrograms, which can be repeated until the desired effect is attained. One bolus dose should not exceed 100micrograms.
Continuous infusion
Initial dose: 25micrograms/minute to 50micrograms/minute. The doses may be increased up to 100micrograms/minute or decreased to maintain the systolic blood pressure close to the normal value.
Doses between 25micrograms/minute and 100micrograms/minute have been assessed to be effective.
80micrograms/ml solution
Intravenous bolus injection
50micrograms to 100micrograms, which can be repeated until the desired effect is attained. One bolus dose should not exceed 100micrograms.
Continuous infusion
Initial dose: 25micrograms/minute to 50micrograms/minute. The doses may be increased up to 100micrograms/minute or decreased to maintain the systolic blood pressure close to the normal value.
Doses between 25micrograms/minute and 100micrograms/minute have been assessed to be effective.
50micrograms/ml solution
Intravenous bolus injection
50micrograms to 100micrograms, which can be repeated until the desired effect is attained. One bolus dose should not exceed 100micrograms.
Continuous infusion
Initial dose: 25micrograms/minute to 50micrograms/minute. The doses may be increased or decreased to maintain the systolic blood pressure close to the normal value.
Doses between 25micrograms/minute and 100micrograms/minute have been assessed to be effective.
Priapism (unlicensed)
Using a 200?micrograms/ml solution, give 100micrograms to 200micrograms by intracavernosal injection every 5 to 10?minutes.
Maximum dose: 1mg per course.
Children
10mg/ml solution
Subcutaneous or intramuscular injection
100micrograms/kg.
The following alternative dosing schedule may be suitable:
Acute hypotension
Subcutaneous or intramuscular injection
Children aged 12 to 18 years
Initial dose: 2mg to 5mg (maximum 5mg per dose). Follow, if necessary after at least 15 minutes, by further doses of 1mg to 10mg
Children aged 1 to 12 years
100micrograms/kg every 1 to 2 hours as needed (maximum 5mg per dose).
By slow intravenous injection (unlicensed)
Dilute to a concentration of 1mg/ml with water for injections.
Children aged 12 to 18 years
100micrograms to 500micrograms. Repeat as necessary after at least 15 minutes.
Children aged 1 to 12 years
5micrograms/kg to 20micrograms/kg (maximum 500micrograms per dose). Repeat as necessary after at least 15 minutes.
By intravenous infusion (unlicensed)
Dilute to a concentration of 20micrograms/ml (with glucose 5% or sodium chloride 0.9%) and administer via a central venous catheter as a continuous infusion using a controlled infusion device.
Children aged 16 to 18 years
Initial dose: Up to 180micrograms/minute. Reduce to 30micrograms/minute to 60micrograms/minute according to response.
Children aged 1 to 16 years
100 to 500nanograms/kg/minute. Titrate according to response.
Administration
Consult product literature for specific information regarding administration.
For priapism (unlicensed indication)
For intracavernosal injection administration.
Contraindications
Within 2 weeks of discontinuing MAOIs
Long QT syndrome
Pregnancy
Severe hypertension
Severe hyperthyroidism
Severe peripheral vascular disease
Torsade de pointes
Precautions and Warnings
Children under 18 years
Elderly
Family history of long QT syndrome
Restricted sodium intake
Angina
Arterial aneurysm
Arteriosclerosis
Bradycardia
Breastfeeding
Cardiac arrhythmias
Cardiogenic shock
Cardiovascular disorder
Cerebral ischaemia
Diabetes mellitus
Electrolyte imbalance
First degree atrioventricular block
Hepatic cirrhosis
History of torsade de pointes
Hypercapnia
Hypertension
Hyperthyroidism
Hypovolaemia
Hypoxia
Ischaemic heart disease
Narrow angle glaucoma
Peripheral vascular disease
Prinzmetal's angina
Recent myocardial infarction
Renal impairment
Second degree atrioventricular block
Severe cardiac failure
Tachycardia
Thrombosis
Correct electrolyte disorders before treatment
Sodium content of formulation may be significant
Not all available brands are licensed for all routes of administration
Not all available products are licensed for all age groups
Not all routes are licensed for all age groups
Administer carefully - extravasation may cause tissue necrosis
If extravasation occurs follow local policy & seek expert help immediately
Consider monitoring ECG in patients at risk of QT prolongation
Monitor arterial pressure
Monitor serum electrolytes
Consider dose adjustment in hepatic cirrhosis
Consider dose reduction in renal impairment
When phenylephrine is used to treat priapism (unlicensed indication) extreme caution is required when treating patients with coronary heart disease, hypertension, cerebral ischaemia, or those taking antidepressants.
Phenylephrine has a longer duration of action than noradrenaline and an excessive vasopressor response may cause a prolonged rise in blood pressure. Monitor blood pressure and flow rate of infusion frequently.
Phenylephrine can induce a reduction in cardiac output. Therefore, care should be exercised in administering to patients with arteriosclerosis, the elderly and to patients with impaired cerebral or coronary circulation.
In patients with reduced cardiac output or coronary vascular disease, vital organs should be closely monitored and dose reduction should be considered when systemic blood pressure is near the lower end of the target.
In patients with serious heart failure or cardiogenic shock, phenylephrine may cause deterioration in the heart failure as a consequence of the induced vasoconstriction (increase in afterload).
Phenylephrine may precipitate angina in patients with angina pectoris.
Pregnancy and Lactation
Pregnancy
Phenylephrine is contraindicated in pregnancy.
The manufacturer does not recommend using phenylephrine during pregnancy. Available reports indicate that alpha-adrenergic receptor agonists slow uterine blood flow. It is also noted that sympathomimetic amines are uterogenic in some animal species, but human teratogenicity has not been suspected. An association between use of phenylephrine in the first trimester and minor defects has been found, with malformations such as inguinal hernia and clubfoot. Administration in late pregnancy or during labour may cause foetal hypoxia and bradycardia. Phenylephrine may also interact with oxytocics or ergot derivatives to produce severe persistent maternal hypertension. Rupture of a cerebral vessel is possible (Briggs, 2015).
To date, the safety of phenylephrine injection has not been established during human pregnancy. Therefore potential risks of use of phenylephrine in pregnancy or by women intending to become pregnant, cannot be ruled out.
Lactation
Use phenylephrine with caution in breastfeeding.
The manufacturer does not recommend breastfeeding whilst taking phenylephrine. Due to the low molecular weight of phenylephrine (around 167), passage into breast milk is expected (Briggs, 2015). LactMed (2018) suggests that intravenous administration of phenylephrine might decrease milk production. The manufacturer notes that administering phenylephrine to mothers may expose the neonate to a risk of cardiovascular and neurological effects but in the event of a single bolus injection during childbirth, breastfeeding is possible.
Side Effects
Agitation
Angina pectoris
Anginal pain
Anxiety
Arrhythmias
Blanching
Bradycardia
Cardiac arrest
Cerebral haemorrhage
Changes in glucose metabolism
Confusion
Coolness of skin
Difficulty in micturition
Dizziness
Dyspnoea
Dysuria
Excitability
Extravasation necrosis
Eye disorder
Flushing
Glaucoma (closed angle)
Headache
Hypersalivation
Hypersensitivity reactions
Hypertension
Hypertensive crisis
Hypotension
Hypoxia
Immune disorder
Increased blood pressure
Insomnia
Local reaction at injection site
Metabolic changes
Mydriasis
Myocardial ischaemia
Nausea
Nervousness
Pallor
Palpitations
Paraesthesia
Peripheral ischaemia
Piloerection
Psychosis
Pulmonary oedema
Reflex bradycardia
Skin tingling
Sweating
Syncope
Tachycardia
Torpor
Tremor
Urinary retention
Vertigo
Vomiting
Weakness
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: May 2016
Reference Sources
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Summary of Product Characteristics: Phenylephrine 0.08mg/ml solution for injection/infusion. Altan Pharma Limited. Revised February 2020.
Summary of Product Characteristics: Phenylephrine 0.1mg/ml solution for injection ampoules. Martindale Pharma Ltd. Revised February 2019.
Summary of Product Characteristics: Phenylephrine 50micrograms/ml solution for injection in Pre-filled syringe. Aguettant Ltd. Revised November 2015.
Summary of Product Characteristics: Phenylephrine 100micrograms/ml solution for injection or infusion. Aguettant Ltd. Revised January 2020.
Summary of Product Characteristics: Phenylephrine injection BP 10mg/ml. Amdipharm Mercury Company Ltd. Revised March 2016.
Summary of Product Characteristics: Phenylephrine 10mg/ml solution for injection or infusion. Beacon Pharmaceuticals. Revised March 2011.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 04 November 2021
US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://www.ncbi.nlm.nih.gov/books/NBK501922/
Phenylephrine. Last revised: 31 October 2018
Last accessed: 04 August 2022
Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
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