Fenylefrin Aguettant
Phenylephrine Injection for Hypotension During Anaesthesia
Quick Facts About Fenylefrin Aguettant
Key Takeaways About Fenylefrin Aguettant
- Hospital-administered vasopressor: Fenylefrin Aguettant is given intravenously only by trained healthcare professionals during anaesthesia to treat sudden drops in blood pressure
- Rapid onset of action: The drug takes effect within approximately 1 minute of IV injection, with a duration of 15–20 minutes, allowing precise blood pressure management during surgery
- MAOI contraindication: Phenylephrine must not be given to patients currently taking or who have recently taken monoamine oxidase inhibitors (MAOIs) within the past 2 weeks, due to risk of severe hypertensive crisis
- Continuous monitoring required: Arterial blood pressure must be monitored throughout treatment, and additional cardiac monitoring is required in patients with heart disease
- Not for children: Fenylefrin Aguettant is not recommended for paediatric use due to insufficient data on safety, efficacy, and dosing in this population
What Is Fenylefrin Aguettant and What Is It Used For?
Fenylefrin Aguettant is an injectable solution containing phenylephrine hydrochloride, used to treat low blood pressure (hypotension) that occurs during general or regional anaesthesia. It belongs to the adrenergic and dopaminergic agents class and works by constricting blood vessels to raise arterial blood pressure.
Phenylephrine, the active substance in Fenylefrin Aguettant, is a selective alpha-1 adrenergic receptor agonist. When injected intravenously, it stimulates alpha-1 receptors located on vascular smooth muscle cells, triggering vasoconstriction – a tightening of the blood vessel walls. This vasoconstriction increases systemic vascular resistance (SVR), which directly raises arterial blood pressure. Unlike adrenaline or noradrenaline, phenylephrine has minimal beta-adrenergic activity at clinical doses, meaning it primarily affects blood vessels without significantly stimulating the heart rate.
During surgical procedures, anaesthesia frequently causes blood pressure to drop to levels that may compromise organ perfusion. Spinal anaesthesia, for example, blocks sympathetic nerve fibres, leading to vasodilation and a rapid fall in blood pressure. General anaesthetic agents such as propofol, sevoflurane, and desflurane also reduce vascular tone and cardiac output. In these situations, prompt intervention with a vasopressor like phenylephrine is essential to maintain adequate blood flow to vital organs including the brain, heart, and kidneys.
Fenylefrin Aguettant is specifically formulated as a ready-to-use 100 micrograms/ml solution in 20 ml glass vials. This pre-diluted concentration eliminates the need for additional dilution steps before administration, reducing the risk of dosing errors and preparation time in the operating theatre. Each vial contains a total of 2,000 micrograms (2 mg) of phenylephrine hydrochloride.
The drug is used exclusively in clinical settings where trained anaesthesia personnel and appropriate haemodynamic monitoring equipment are available. It is not a self-administered medication. The anaesthetist or anaesthesia nurse titrates the dose according to the patient's individual blood pressure response, adjusting the infusion rate or bolus doses as needed to maintain the target mean arterial pressure (MAP) throughout the surgical procedure.
Phenylephrine has been used as a vasopressor in anaesthesia for over 70 years and is considered one of the standard first-line agents for treating anaesthesia-induced hypotension. The European Society of Anaesthesiology and Intensive Care (ESAIC) and the American Society of Anesthesiologists (ASA) both include phenylephrine in their perioperative guidelines. The ready-to-use formulation of Fenylefrin Aguettant is designed to minimise medication errors in time-critical situations.
What Should You Know Before Receiving Fenylefrin Aguettant?
Before receiving Fenylefrin Aguettant, your anaesthetist will review your complete medical history, current medications, and any allergies. The drug must not be given if you have severe hypertension, severe peripheral vascular disease, are taking MAO inhibitors, or have severe hyperthyroidism.
Contraindications
You will not receive Fenylefrin Aguettant if any of the following conditions apply:
- Allergy to phenylephrine hydrochloride or any of the other ingredients in the formulation – symptoms of an allergic reaction may include itching, rash, facial swelling, or difficulty breathing
- Severe hypertension (very high blood pressure) – phenylephrine would further elevate blood pressure to potentially dangerous levels
- Severe peripheral vascular disease (poor blood circulation in the extremities) – the vasoconstrictive effects could critically reduce blood flow to affected limbs
- Current or recent use of monoamine oxidase inhibitors (MAOIs), including within 2 weeks of stopping treatment – examples include iproniazid and nialamide. MAOIs dramatically potentiate the pressor effect of phenylephrine, potentially causing life-threatening hypertensive crisis
- Severe hyperthyroidism (overactive thyroid gland) – patients with uncontrolled thyroid overactivity may have exaggerated cardiovascular responses to adrenergic agents
Warnings and Precautions
Your anaesthetist should be informed if you have or have had any of the following conditions, as extra caution or dose adjustments may be needed:
- Elderly age – older patients may be more sensitive to the blood pressure-raising effects and may require lower doses
- Diabetes mellitus – phenylephrine may affect blood glucose levels and peripheral circulation
- Arterial hypertension (high blood pressure) – even non-severe hypertension warrants careful dose titration
- Uncontrolled hyperthyroidism – elevated thyroid hormone levels may amplify the cardiovascular effects
- Atherosclerosis (hardening and thickening of blood vessel walls) – vasoconstriction may worsen tissue ischaemia in affected areas
- Cerebrovascular insufficiency – conditions causing poor blood circulation to the brain require careful blood pressure management
- Aneurysm – sudden increases in blood pressure may place excessive stress on weakened vessel walls
- Heart disease, including chronic heart disease, mild circulatory impairment, cardiac arrhythmias, tachycardia (fast heart rate), bradycardia (slow heart rate), partial heart block, or angina pectoris – phenylephrine can affect cardiac function and rhythm
- Narrow-angle glaucoma (a rare eye condition) – phenylephrine can increase intraocular pressure
In patients with severe heart failure, phenylephrine may worsen the condition by increasing afterload (the resistance the heart must work against to pump blood). The vasoconstriction caused by phenylephrine increases the workload on an already weakened heart. Your anaesthetist will carefully weigh the risks and benefits and may choose an alternative vasopressor if you have significant heart failure.
During treatment with Fenylefrin Aguettant, your arterial blood pressure will be continuously monitored. If you have pre-existing heart disease, additional monitoring of cardiac function – including electrocardiography (ECG) and possibly cardiac output monitoring – will be performed to ensure your heart is responding safely to the medication.
Use in Children
Fenylefrin Aguettant is not recommended for use in children due to insufficient data on efficacy, safety, and appropriate dosing recommendations in the paediatric population. If a vasopressor is required during paediatric anaesthesia, the anaesthetist will select an alternative agent with established paediatric dosing guidelines, such as ephedrine or adrenaline, based on current evidence and clinical protocols.
Pregnancy and Breastfeeding
The safety of Fenylefrin Aguettant during pregnancy has not been fully established. However, it may be used during pregnancy if the clinical situation requires it, such as for the treatment of hypotension during caesarean section under spinal anaesthesia. In fact, international obstetric anaesthesia guidelines – including those from the National Institute for Health and Care Excellence (NICE) and the Obstetric Anaesthetists' Association (OAA) – recommend phenylephrine as one of the first-line vasopressors for managing spinal anaesthesia-induced hypotension during caesarean delivery, as it has been shown to maintain foetal acid-base status better than some alternative vasopressors.
Regular use of Fenylefrin Aguettant during breastfeeding is not recommended. However, if the drug is administered as a single dose during delivery, subsequent breastfeeding is considered possible. If you are pregnant or breastfeeding, planning to become pregnant, or think you may be pregnant, your anaesthetist will discuss the risks and benefits with you before administering this medication.
Driving and Operating Machinery
Fenylefrin Aguettant is administered during anaesthesia, so the question of driving and operating machinery relates primarily to the post-anaesthetic recovery period rather than the vasopressor itself. You should follow your anaesthetist's specific advice regarding when it is safe to drive or operate machinery after your procedure. The effects of the anaesthesia – not the phenylephrine – are the primary consideration. Most guidelines recommend not driving for at least 24 hours after general anaesthesia.
Sodium Content
Fenylefrin Aguettant contains 78 mg of sodium (the main component of table salt) per 20 ml vial. This is equivalent to approximately 4% of the recommended maximum daily sodium intake for adults. This should be taken into account for patients on a sodium-restricted diet, although a single intraoperative dose is unlikely to have a clinically meaningful impact on total daily sodium intake.
How Does Fenylefrin Aguettant Interact with Other Drugs?
Phenylephrine has significant interactions with MAO inhibitors, certain antidepressants, ergot alkaloids, inhaled anaesthetics, and several other drug classes. Your anaesthetist will review all current medications before administration. The most dangerous interaction is with MAOIs, which is an absolute contraindication.
Phenylephrine is metabolised primarily by monoamine oxidase (MAO) in the liver and gastrointestinal tract. Drugs that inhibit MAO or that affect adrenergic neurotransmission can significantly alter the effects of phenylephrine. Additionally, because phenylephrine is typically used alongside anaesthetic agents, interactions with these drugs are of particular clinical importance. The following table summarises the most significant drug interactions.
Major Interactions (Contraindicated or High Risk)
| Drug / Class | Examples | Effect | Recommendation |
|---|---|---|---|
| Non-selective MAO inhibitors | Iproniazid, nialamide | Dramatically increased and prolonged pressor response; risk of severe hypertensive crisis | Contraindicated. Do not use phenylephrine within 2 weeks of MAOI therapy |
| Reversible MAO-A inhibitors | Moclobemide, toloxatone | Potentiation of the pressor effect of phenylephrine | Avoid combination; risk of severe hypertension |
| Linezolid | Linezolid (antibiotic) | MAO-inhibiting activity potentiates phenylephrine effect | Avoid combination; monitor blood pressure if unavoidable |
| Ergot alkaloids | Dihydroergotamine, ergotamine, methylergometrine, methysergide | Additive vasoconstriction; risk of severe hypertension and peripheral ischaemia | Avoid combination whenever possible |
| Tricyclic antidepressants | Imipramine | Enhanced pressor response due to inhibition of noradrenaline reuptake | Use with extreme caution; reduce phenylephrine dose |
| SNRIs | Milnacipran, venlafaxine | Potentiation of pressor effect via noradrenaline reuptake inhibition | Use with caution; careful dose titration |
Moderate Interactions (Use with Caution)
| Drug / Class | Examples | Effect | Recommendation |
|---|---|---|---|
| Volatile anaesthetics | Halothane, sevoflurane, desflurane, isoflurane, enflurane | Sensitise the myocardium to catecholamines; increased risk of cardiac arrhythmias (especially with halothane) | Use reduced doses of phenylephrine; continuous cardiac monitoring |
| Dopaminergic anti-Parkinson drugs | Bromocriptine, lisuride, pergolide | Potential for enhanced or altered pressor response | Monitor blood pressure closely |
| Prolactin inhibitors | Cabergoline | Potential interaction via dopaminergic/adrenergic pathways | Monitor blood pressure closely |
| Guanethidine | Guanethidine (antihypertensive) | Enhanced pressor effect of phenylephrine due to denervation supersensitivity | Use reduced doses; careful blood pressure monitoring |
| Cardiac glycosides | Digoxin | Increased risk of cardiac arrhythmias when combined with vasopressor | ECG monitoring; use lowest effective dose |
| Quinidine | Quinidine (antiarrhythmic) | Potential for altered cardiac conduction and arrhythmia risk | ECG monitoring during co-administration |
| Oxytocin | Oxytocin (used during labour) | Both agents can affect blood pressure; additive cardiovascular effects | Common combination in obstetric anaesthesia; careful BP monitoring |
| Sibutramine | Sibutramine (appetite suppressant) | Potential for enhanced adrenergic effects and hypertension | Inform anaesthetist; monitor blood pressure |
What Is the Correct Dosage of Fenylefrin Aguettant?
Fenylefrin Aguettant is administered intravenously by trained healthcare professionals only. The dose is individualised and titrated to the desired blood pressure response. There is no fixed standard dose – the anaesthetist adjusts the amount based on continuous blood pressure monitoring during surgery.
Fenylefrin Aguettant is a ready-to-use solution containing 100 micrograms of phenylephrine hydrochloride per millilitre. It can be administered as intermittent intravenous bolus injections or as a continuous intravenous infusion, depending on the clinical situation and the anaesthetist's preference. The drug is always given under direct medical supervision with continuous arterial blood pressure monitoring.
Adults
For adult patients, the anaesthetist will determine the appropriate dose and may repeat or adjust it until the desired blood pressure response is achieved. Common dosing approaches in clinical practice include:
- Bolus injection: 50–200 micrograms (0.5–2 ml) administered as a slow IV push over at least 15–30 seconds, repeated every 5–10 minutes as needed
- Continuous infusion: 25–100 micrograms per minute, titrated to the target mean arterial pressure. The infusion rate is adjusted in real time based on the patient's haemodynamic response
The specific dose selected depends on multiple factors, including the type of anaesthesia (general vs. regional), the patient's baseline blood pressure, cardiac function, volume status, and the surgical procedure being performed. The anaesthetist aims to maintain a mean arterial pressure (MAP) typically above 65 mmHg, though this target may be adjusted for individual patients.
Patients with Kidney Impairment
Lower doses of phenylephrine may be required in patients with impaired kidney (renal) function. The kidneys play a role in the clearance of phenylephrine metabolites, and reduced renal function may lead to prolonged drug effects. Your anaesthetist will take your kidney function into account when determining the appropriate dose and will monitor your blood pressure response carefully.
Patients with Liver Impairment
Paradoxically, higher doses of phenylephrine may be needed in patients with impaired liver function. This is because the liver is the primary site of phenylephrine metabolism via monoamine oxidase. When liver function is reduced, the rate of drug breakdown may increase through alternative pathways, or the pharmacodynamic response may be altered. The anaesthetist will titrate the dose to effect, guided by continuous blood pressure monitoring.
Elderly Patients
Treatment of elderly patients should be undertaken with particular caution. Older patients are often more sensitive to the vasoconstrictive effects of phenylephrine and may be at greater risk of excessive blood pressure elevation. They are also more likely to have underlying cardiovascular disease, atherosclerosis, and reduced autonomic reflexes. The anaesthetist will typically start with a lower dose and titrate slowly, with careful monitoring of both blood pressure and heart rate.
Children
Fenylefrin Aguettant is not recommended for use in children due to insufficient data on efficacy, safety, and dosing in the paediatric population. The manufacturer has not established paediatric dosing guidelines for this formulation.
Overdose
In the event of overdose or excessive blood pressure elevation, the following symptoms may occur:
- Cardiovascular: Palpitations, cardiac arrhythmias (including tachycardia), severe hypertension
- Neurological: Headache, hallucinations, paranoid psychosis (in extreme cases)
- Gastrointestinal: Nausea, vomiting
Because Fenylefrin Aguettant is administered by trained professionals in a monitored clinical environment, overdose is rare and can be quickly managed. Treatment of overdose is symptomatic and supportive, and may include the use of short-acting alpha-adrenergic blocking agents such as phentolamine to counteract excessive vasoconstriction. If you or a family member has any concerns about the medication, speak with the anaesthesia team.
What Are the Side Effects of Fenylefrin Aguettant?
Like all medications, phenylephrine can cause side effects, although not everyone experiences them. The most clinically significant side effects include high blood pressure, slow or fast heart rate, headache, and nausea. Serious but rare effects include chest pain, cardiac arrhythmias, cerebral haemorrhage, and psychosis.
Side effects from intravenous phenylephrine are generally dose-dependent and are managed in real time by the anaesthesia team. Because the drug has a short duration of action (15–20 minutes), most side effects resolve quickly once the infusion is stopped or the dose is reduced. The frequency of individual side effects for this specific formulation has not been precisely determined in clinical trials (frequency “not known”), but the following effects have been reported based on post-marketing surveillance and clinical experience with intravenous phenylephrine.
Serious Side Effects
Contact the medical team immediately or seek urgent medical help if any of the following occur (these are rare but potentially life-threatening):
Serious (Seek Immediate Help)
Frequency not known – reported in post-marketing surveillance
- Chest pain or angina pectoris
- Irregular heartbeat (cardiac arrhythmias)
- Sensation of the heart pounding in the chest (palpitations)
- Cerebral haemorrhage (speech disturbances, dizziness, paralysis on one side of the body)
- Psychosis (loss of contact with reality)
- Pulmonary oedema (fluid in the lungs, causing severe breathing difficulty)
Other Side Effects
The following side effects have also been reported. Your anaesthesia team will monitor for these and manage them accordingly:
Cardiovascular
Frequency not known
- Slow heart rate (bradycardia)
- Fast heart rate (tachycardia)
- High blood pressure (hypertension)
Nervous System & Psychiatric
Frequency not known
- Headache
- Nervousness
- Anxiety
- Confusion
- Agitation (restlessness)
- Insomnia (difficulty sleeping)
- Tremor (shaking)
- Paraesthesia (tingling or prickling sensation in the skin)
- Irritability
Gastrointestinal & Other
Frequency not known
- Nausea
- Vomiting
- Sweating
- Pallor (skin paleness)
- Goosebumps (piloerection)
- Difficulty breathing
- Muscle weakness
- Difficulty urinating or complete urinary retention
- Tissue damage at the injection site
Eye & Immune
Frequency not known
- Excessively dilated pupils (mydriasis)
- Increased eye pressure (worsening of glaucoma)
- Hypersensitivity reaction (allergic reaction)
It is important to report suspected side effects after a medicine has been authorised. This allows ongoing monitoring of the medicine's benefit-risk balance. Healthcare professionals and patients can report suspected adverse reactions to their national medicines regulatory authority (e.g., the MHRA in the United Kingdom, the EMA in the European Union, or the FDA in the United States).
How Should Fenylefrin Aguettant Be Stored?
Fenylefrin Aguettant requires no special temperature storage conditions but must be stored in the original carton to protect from light. It must be kept out of the sight and reach of children and must not be used after the expiry date.
The following storage guidelines apply to Fenylefrin Aguettant:
- Temperature: No special temperature storage requirements. Store at room temperature
- Light protection: Keep the vial in the outer carton to protect from light, as phenylephrine may degrade when exposed to light
- Expiry date: Do not use after the expiry date printed on the label (after “EXP”). The expiry date refers to the last day of the stated month. Your doctor or nurse will check the expiry before use
- Visual inspection: The solution should be clear and colourless. Do not use if there are visible signs of deterioration, particles, or discolouration
- Single use: Once opened, any unused solution should be discarded immediately. Do not store partially used vials for later use
- Children: Keep out of the sight and reach of children
- Disposal: Unused medicine or waste material should be disposed of in accordance with local requirements. Do not dispose via household waste or wastewater
In practice, because Fenylefrin Aguettant is a hospital-use medication, storage and handling are managed by pharmacy and operating theatre staff according to institutional protocols. Patients do not need to store this medication at home.
What Does Fenylefrin Aguettant Contain?
Each millilitre of Fenylefrin Aguettant contains phenylephrine hydrochloride equivalent to 100 micrograms of phenylephrine. The solution also contains sodium chloride, sodium citrate, citric acid monohydrate, sodium hydroxide, and water for injections as excipients.
Active Ingredient
The active substance is phenylephrine hydrochloride. Each 20 ml glass vial contains phenylephrine hydrochloride equivalent to 2,000 micrograms (2 mg) of phenylephrine total, providing a concentration of 100 micrograms per millilitre.
Other Ingredients (Excipients)
The other ingredients are:
- Sodium chloride – used to make the solution isotonic (matching body fluid concentration)
- Sodium citrate – acts as a buffering agent to maintain the correct pH
- Citric acid monohydrate – buffering agent
- Sodium hydroxide – used for pH adjustment
- Water for injections – the solvent
Appearance and Packaging
Fenylefrin Aguettant is a clear, colourless solution for injection supplied in 20 ml transparent Type II glass vials sealed with a rubber stopper and an aluminium cap. The vials are available in cartons of 1 or 10. Not all pack sizes may be marketed in all countries.
The marketing authorisation holder and manufacturer is Laboratoire Aguettant, based in Lyon, France. The product is distributed across multiple European markets and is available through hospital pharmacy channels.
Frequently Asked Questions About Fenylefrin Aguettant
Phenylephrine and ephedrine are both vasopressors used during anaesthesia, but they work through different mechanisms. Phenylephrine is a pure alpha-1 adrenergic agonist – it raises blood pressure primarily by constricting blood vessels without directly increasing heart rate. Ephedrine, on the other hand, has both direct and indirect adrenergic effects, stimulating both alpha and beta receptors, which increases both blood pressure and heart rate. In obstetric anaesthesia, phenylephrine is generally preferred because it produces less foetal acidosis compared to ephedrine. The choice between them depends on the clinical scenario and the patient's cardiovascular status.
It depends on the type of anaesthesia. If you are under general anaesthesia (fully asleep), you will not be aware of the injection. If you are having a regional anaesthetic (such as a spinal or epidural), you may be awake or mildly sedated but you are unlikely to feel the phenylephrine being administered through your intravenous line. The anaesthesia team monitors your blood pressure continuously and will administer phenylephrine as needed to keep you safe during the procedure. You may be informed that a medication is being given if you are awake.
Intravenous phenylephrine has a very rapid onset of action – typically within 1 minute of injection. This makes it ideal for the acute management of blood pressure drops during surgery. The duration of effect following a single bolus dose is approximately 15 to 20 minutes. Because of this relatively short duration, the anaesthetist may need to administer repeated doses or switch to a continuous infusion for prolonged blood pressure support during longer procedures.
Yes, phenylephrine is one of the first-line vasopressors recommended for treating spinal anaesthesia-induced hypotension during caesarean section. International guidelines, including those from the National Institute for Health and Care Excellence (NICE) and the Obstetric Anaesthetists' Association (OAA), support its use in this setting. Studies have shown that phenylephrine maintains foetal acid-base status better than some alternatives such as ephedrine, making it a preferred choice. The anaesthetist will carefully titrate the dose to maintain maternal blood pressure while ensuring adequate placental blood flow.
Before any surgery requiring anaesthesia, you should inform your anaesthetist about all medications you are currently taking, including prescription drugs, over-the-counter medicines, and herbal supplements. This is particularly important for MAO inhibitors (used for depression), antidepressants, migraine medications, blood pressure medications, heart medications, and Parkinson's disease treatments. Also inform them about any known drug allergies, heart conditions, high blood pressure, thyroid problems, diabetes, glaucoma, or vascular disease. This information helps the anaesthetist select the safest vasopressor and dosing strategy for you.
Phenylephrine given intravenously during anaesthesia is a short-acting medication with a duration of only 15–20 minutes per dose. It is eliminated from the body relatively quickly and is not associated with long-term side effects. Any side effects that occur during administration – such as changes in blood pressure or heart rate – are typically transient and resolve once the drug wears off or the infusion is stopped. Long-term complications from a single intraoperative exposure are extremely rare.
References and Sources
- European Medicines Agency (EMA). Summary of Product Characteristics – Phenylephrine hydrochloride solution for injection. Available from: www.ema.europa.eu
- Laboratoire Aguettant. Fenylefrin Aguettant 0.1 mg/ml – Product Information. Lyon, France.
- Kinsella SM, Carvalho B, Dyer RA, et al. International consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia. Anaesthesia. 2018;73(1):71-92. doi:10.1111/anae.14080
- Ngan Kee WD, Lee SWY, Ng FF, et al. Randomized double-blinded comparison of norepinephrine and phenylephrine for maintenance of blood pressure during spinal anesthesia for cesarean delivery. Anesthesiology. 2015;122(4):736-745.
- National Institute for Health and Care Excellence (NICE). Caesarean birth (NG192). Published November 2021, updated September 2023. Available from: www.nice.org.uk/guidance/ng192
- European Society of Anaesthesiology and Intensive Care (ESAIC). Guidelines on perioperative care. Available from: www.esaic.org
- World Health Organization (WHO). WHO Model Formulary. Available from: www.who.int
- British National Formulary (BNF). Phenylephrine hydrochloride – Monograph. National Institute for Health and Care Excellence. Available from: bnf.nice.org.uk
- U.S. Food and Drug Administration (FDA). Phenylephrine Hydrochloride Injection – Prescribing Information. Available from: www.fda.gov
- Sessler DI, Bloomstone JA, Aronson S, et al. Perioperative Quality Initiative consensus statement on intraoperative blood pressure, risk and outcomes for elective surgery. British Journal of Anaesthesia. 2019;122(5):563-574. doi:10.1016/j.bja.2019.01.013
Editorial Team
Medical Review
iMedic Medical Review Board – Specialists in Anaesthesiology and Clinical Pharmacology
Evidence Standard
Level 1A – Systematic reviews, meta-analyses, and randomised controlled trials (GRADE framework)
Guidelines Followed
ESA, ASA, NICE, OAA, WHO – International perioperative and pharmacological guidelines
Independence
No commercial funding. No pharmaceutical company sponsorship. Independent editorial content