Phenylephrine Uses, Dosage, Side Effects & Warnings | DrugsAtlas
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DRUG NAME: Phenylephrine
Therapeutic Class: Sympathomimetic agent
Subclass: Selective α1-adrenergic receptor agonist
Speciality: Anaesthesiology
Schedule (India): Schedule H
Route(s): Oral, Intravenous, Intramuscular, Subcutaneous, Topical (nasal, ophthalmic)
Formulations Available in India:
• Tablets: 5 mg, 10 mg (mostly in FDCs for cold/cough)
• Injection: 10 mg/mL ampoule (1 mL)
• Nasal drops/spray: 0.25%, 0.5%
• Ophthalmic drops: 2.5%, 5%, 10%
• Tablets: 5 mg, 10 mg (mostly in FDCs for cold/cough)
• Injection: 10 mg/mL ampoule (1 mL)
• Nasal drops/spray: 0.25%, 0.5%
• Ophthalmic drops: 2.5%, 5%, 10%
INDICATIONS + DOSING — FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India)
1. Hypotension During Anaesthesia / Perioperative Setting
| Parameter | IV Bolus | IV Infusion |
|---|---|---|
| Starting dose | 50–100 mcg IV bolus | 0.25–0.5 mcg/kg/min |
| Titration | May repeat every 1–2 minutes as needed | Increase by 0.1–0.2 mcg/kg/min every 5–10 min to target MAP |
| Usual maintenance dose | Not applicable (bolus PRN) | 0.5–2 mcg/kg/min |
| Maximum dose | 200 mcg per bolus | 5 mcg/kg/min |
Clinical Notes:
- Requires continuous arterial BP and HR monitoring
- Preferred vasopressor when hypotension occurs without tachycardia
- Causes reflex bradycardia — have atropine available
- Central venous access preferred for infusion to avoid extravasation
2. Spinal Anaesthesia-Induced Hypotension in Obstetrics (Caesarean Section)
| Parameter | Recommendation |
|---|---|
| Starting dose | 50–100 mcg IV bolus at onset of hypotension |
| Titration | Repeat every 1–2 minutes as needed |
| Usual maintenance dose | Infusion 25–50 mcg/min, or intermittent boluses |
| Maximum dose | No fixed maximum; titrate to maternal BP response |
Clinical Notes:
- Now considered first-line vasopressor for spinal-induced hypotension during caesarean delivery (AIIMS Obstetric Anaesthesia protocols)
- Maintains uteroplacental perfusion better than ephedrine in most cases
- Monitor fetal heart rate continuously
- Left uterine displacement must be maintained
3. Nasal Congestion (Short-term Symptomatic Relief)
| Parameter | Recommendation |
|---|---|
| Starting dose | 2–3 drops or sprays of 0.25%–0.5% solution per nostril |
| Titration | Not applicable |
| Usual maintenance dose | 2–3 drops/sprays per nostril every 4–6 hours PRN |
| Maximum dose | 4 applications per day |
Clinical Notes:
- Limit use to ≤5 days to prevent rhinitis medicamentosa (rebound congestion)
- Avoid in patients with uncontrolled hypertension
- Saline nasal drops preferred as first-line in most cases
4. Mydriasis for Ophthalmic Examination / Procedures
| Concentration | Indication | Dose |
|---|---|---|
| 2.5% | Routine diagnostic mydriasis, fundoscopy | 1 drop; may repeat after 15–30 minutes if needed |
| 5% | Moderate dilation required | 1 drop; repeat once if required |
| 10% | Resistant cases, breaking posterior synechiae | Specialist use only; 1 drop with cardiovascular monitoring |
Clinical Notes:
- 2.5% concentration preferred for routine use
- 10% concentration carries significant systemic absorption risk — monitor BP and HR
- Often used in combination with tropicamide for synergistic effect
- Contraindicated in narrow-angle glaucoma
Secondary Indications – Adults (Off-label, if any)
Ischaemic Priapism — OFF-LABEL, Specialist Only
| Parameter | Recommendation |
|---|---|
| Route | Intracavernosal injection |
| Starting dose | 100–200 mcg phenylephrine diluted in 1 mL normal saline |
| Titration | Repeat every 5–10 minutes as needed |
| Maximum dose | 1000 mcg total |
| Duration | Until detumescence achieved |
Evidence basis: Urological Society of India guidelines; American Urological Association recommendations. Phenylephrine preferred due to selective α1 activity with minimal cardiac effects.
⚠️ Specialist (Urologist) administration only.
PAEDIATRIC DOSING (Specialist Only)
Primary Indications
1. Hypotension During Anaesthesia
| Age Group | Bolus Dose | Infusion Dose |
|---|---|---|
| Neonates | 0.5–1 mcg/kg IV | 0.1–0.5 mcg/kg/min |
| Infants & Children | 1–2 mcg/kg IV | 0.1–0.5 mcg/kg/min |
| Adolescents | 1–2 mcg/kg IV (max 100 mcg) | 0.5–2 mcg/kg/min |
| Parameter | Recommendation |
|---|---|
| Starting dose | 1 mcg/kg IV slow bolus |
| Titration | Repeat every 2–5 minutes; initiate infusion if persistent hypotension |
| Usual maintenance dose | 0.1–0.5 mcg/kg/min |
| Maximum dose | 2 mcg/kg/bolus; 1 mcg/kg/min infusion |
Safety Monitoring:
- Continuous ECG, BP, and SpO2 monitoring mandatory
- Watch for reflex bradycardia
- Central line preferred for infusion
2. Nasal Congestion (Short-term)
| Age Group | Concentration | Dose |
|---|---|---|
| 2–6 years | 0.125%–0.25% | 1–2 drops per nostril every 6 hours PRN |
| 6–12 years | 0.25% | 2–3 drops per nostril every 6 hours PRN |
| >12 years | 0.25%–0.5% | 2–3 drops per nostril every 4–6 hours PRN |
Clinical Notes:
- Maximum duration: 3 days in children
- NOT recommended below 2 years without specialist supervision (IAP, MoHFW guidelines)
- Saline drops remain first-line for paediatric nasal congestion
Secondary Indications – Paediatric Doses (Off-label, if any)
Mydriasis for Fundoscopy in Neonates — OFF-LABEL, Specialist Only
| Parameter | Recommendation |
|---|---|
| Dose | 1 drop of 2.5% phenylephrine diluted 1:1 with sterile water (final 1.25%) |
| Frequency | Single application; may repeat once after 15–20 minutes |
| Combination | Usually combined with cyclopentolate 0.5% or tropicamide 0.5% |
Evidence basis: Neonatal ophthalmology protocols (AIIMS, Sankara Nethralaya); dilution reduces systemic absorption risk.
⚠️ Paediatric ophthalmologist or neonatologist supervision required.
RENAL ADJUSTMENT
| Renal Status | Recommendation |
|---|---|
| Mild to moderate impairment | No dosage adjustment required |
| Severe impairment / ESRD | Use with caution; enhanced pressor sensitivity possible |
| Haemodialysis | Not significantly dialyzed; monitor BP closely |
HEPATIC ADJUSTMENT
| Hepatic Status | Recommendation |
|---|---|
| Mild impairment | No routine adjustment; standard monitoring |
| Moderate impairment | Use with caution; may have prolonged effect |
| Severe impairment | Use cautiously; increased sensitivity possible due to reduced first-pass metabolism (oral route); closer BP monitoring required |
CONTRAINDICATIONS
- Severe hypertension (uncontrolled)
- Ventricular tachycardia or ventricular fibrillation
- Concurrent use with MAO inhibitors (within 14 days)
- Narrow-angle glaucoma (ophthalmic preparations)
- Known hypersensitivity to phenylephrine or any excipient
- Severe coronary artery disease (relative — use with extreme caution)
CAUTIONS
- Diabetes mellitus — risk of hyperglycaemia with systemic use
- Ischaemic heart disease — increases myocardial oxygen demand
- Hyperthyroidism — exaggerated α1-adrenergic response
- Elderly — enhanced pressor sensitivity
- Prostatic hypertrophy — may worsen urinary retention
- Prolonged nasal use (>5 days) — rhinitis medicamentosa
- Extravasation of IV infusion — risk of tissue necrosis
- Closed-angle glaucoma risk factors (ophthalmic use)
PREGNANCY
| Parameter | Information |
|---|---|
| Risk category | Category C (Use only if benefit outweighs risk) |
| Overall safety | May reduce uteroplacental blood flow via α1-mediated vasoconstriction |
| Preferred alternatives | For nasal congestion: saline drops; for systemic hypotension: phenylephrine now preferred over ephedrine in spinal anaesthesia for caesarean |
| When it may be used | Spinal-induced hypotension during caesarean section (first-line); acute perioperative hypotension under monitoring |
| Monitoring | Continuous fetal heart rate monitoring; maternal BP |
LACTATION
| Parameter | Information |
|---|---|
| Compatibility | Likely compatible with short-term topical use (nasal, ophthalmic) |
| Preferred alternatives | Saline nasal drops for congestion |
| Expected levels in milk | Low systemic absorption with topical use; minimal expected in breast milk |
| What to monitor in infant | Irritability, feeding difficulties, tachycardia (if mother on high-dose oral FDCs) |
Note: Avoid prolonged use of oral phenylephrine-containing FDC cold preparations during breastfeeding.
ELDERLY
| Parameter | Recommendation |
|---|---|
| Recommended starting dose | 25–50 mcg IV bolus; 0.1–0.25 mcg/kg/min infusion |
| Need for slower titration | Yes — exaggerated pressor response common |
| Extra risks | Reflex bradycardia, hypertensive overshoot, cardiac ischaemia, urinary retention, confusion |
Clinical Note: Monitor ECG continuously; have atropine readily available for significant bradycardia.
MAJOR DRUG INTERACTIONS
| Interacting Drug/Class | Mechanism | Recommendation |
|---|---|---|
| MAO inhibitors (phenelzine, tranylcypromine, linezolid, methylene blue) | Impaired norepinephrine metabolism; hypertensive crisis risk | CONTRAINDICATED — avoid within 14 days |
| Tricyclic antidepressants (amitriptyline, imipramine) | Enhanced pressor response via inhibited neuronal uptake | Reduce phenylephrine dose by 50%; close monitoring |
| Ergot alkaloids (ergotamine, methylergometrine) | Additive vasoconstriction; severe ischaemia risk | Avoid combination |
| Oxytocin (high doses) | Additive vasopressor effect; hypertension risk | Use cautiously; monitor BP |
MODERATE DRUG INTERACTIONS
| Interacting Drug/Class | Effect | Recommendation |
|---|---|---|
| Beta-blockers | Unopposed α1 effect; exaggerated hypertension and reflex bradycardia | Monitor BP and HR closely |
| Digoxin | Increased arrhythmia risk | ECG monitoring with IV phenylephrine |
| Volatile anaesthetics (halothane, isoflurane, sevoflurane) | Sensitised myocardium; arrhythmogenic potential | Use lower phenylephrine doses |
| Antihypertensives | Blunted hypotensive effect of antihypertensives | Monitor BP; may need antihypertensive dose adjustment |
| NSAIDs | May antagonise antihypertensive therapy when combined with oral phenylephrine | Avoid prolonged combination |
COMMON ADVERSE EFFECTS
- Hypertension
- Reflex bradycardia
- Headache
- Anxiety, restlessness
- Nausea
- Nasal burning or irritation (nasal drops)
- Stinging, blurred vision (ophthalmic drops)
- Pallor
SERIOUS ADVERSE EFFECTS
- Hypertensive crisis (especially with MAO inhibitors)
- Myocardial ischaemia / infarction (dose-dependent, rare)
- Cardiac arrhythmias
- Cerebrovascular accident (overdose/misuse)
- Acute angle-closure glaucoma (ophthalmic — in susceptible patients)
- Extravasation necrosis (IV) — requires immediate phentolamine infiltration
- Pulmonary oedema (with severe hypertension)
⚠️ Extravasation management: Infiltrate area with phentolamine 5–10 mg diluted in 10–15 mL normal saline within 12 hours.
MONITORING REQUIREMENTS
| Timing | Parameters |
|---|---|
| Baseline | Blood pressure, heart rate, ECG (if IV use planned), assess for contraindications |
| During IV use | Continuous arterial BP, continuous ECG, HR monitoring every 1–2 minutes during bolus titration |
| Nasal/ophthalmic use | Duration of use (limit ≤5 days for nasal); intraocular pressure if repeated ophthalmic use |
| Long-term oral FDC use | Blood pressure monitoring; avoid in patients with hypertension |
BRANDS AVAILABLE IN INDIA
Injectable:
- Fenox (Neon Laboratories)
- Phenylephrine Injection IP (various manufacturers)
Nasal Preparations:
- Nasivion S Plus (phenylephrine + chlorpheniramine)
- Otrivin-P (limited)
Ophthalmic Preparations:
- Phenylephrine Eye Drops 2.5%, 5%, 10% (various manufacturers)
- Tropicacyl Plus (tropicamide + phenylephrine FDC)
- Mydcombi (tropicamide + phenylephrine)
Oral FDCs (cold/cough):
- Sinarest (phenylephrine + paracetamol + chlorpheniramine)
- Wikoryl (phenylephrine + paracetamol + chlorpheniramine)
- D-Cold Total (phenylephrine + paracetamol + cetirizine + caffeine)
- Coldact (phenylephrine combinations)
PRICE RANGE (INR)
| Formulation | Price Range |
|---|---|
| Injection 10 mg/mL (1 mL ampoule) | ₹15–40 per ampoule |
| Nasal drops 0.25%–0.5% (10 mL) | ₹30–70 per bottle |
| Ophthalmic drops 2.5% (5 mL) | ₹40–80 per bottle |
| Ophthalmic drops 10% (5 mL) | ₹60–120 per bottle |
| Oral FDC tablets | ₹2–6 per tablet |
Note: Some FDCs under NPPA price control. Injectable available in government supply.
CLINICAL PEARLS
- First-line vasopressor for spinal anaesthesia-induced hypotension during caesarean section — preferred over ephedrine in current Indian obstetric anaesthesia practice
- Reflex bradycardia is common with IV bolus — always have atropine readily available
- Avoid intranasal use beyond 5 days to prevent rebound congestion (rhinitis medicamentosa)
- Use 2.5% ophthalmic drops for routine mydriasis; reserve 10% for posterior synechiae or inadequate dilation under specialist supervision with cardiovascular monitoring
- For IV extravasation, immediate phentolamine infiltration can prevent tissue necrosis
- In priapism, phenylephrine is preferred over epinephrine due to selective α1 activity and lower cardiac risk
TAGS
Phenylephrine; alpha-agonist; vasopressor; nasal decongestant; mydriatic; anaesthesia; obstetric anaesthesia; perioperative; hypotension; ENT; ophthalmology; Schedule H
VERSION
RxIndia v0.9 — 18 Feb 2026
REFERENCES
- CDSCO Approved Formulations Database
- Indian Pharmacopoeia (IP)
- National Formulary of India (NFI)
- AIIMS Anaesthesia Drug Protocols
- AIIMS Obstetric Anaesthesia Guidelines
- IAP Guidelines — Paediatric Cold Management
- Urological Society of India Guidelines — Priapism Management
- Goodman & Gilman's The Pharmacological Basis of Therapeutics
- API Textbook of Medicine
- Harrison's Principles of Internal Medicine
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Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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