Atropine Sulphate

Atropine Sulphate is a competitive muscarinic receptor antagonist that blocks acetylcholine at peripheral muscarinic receptors. It abolishes bradycardia, reduces heart block from vagal activity, relaxes smooth muscles, and reduces glandular secretions.

As an ophthalmic preparation, 1% solution is used for cycloplegia and mydriasis, while 0.01% solution slows myopia progression in children aged 4-14 years. It acts via muscarinic receptors on scleral fibroblasts to induce scleral remodeling and reduce axial length elongation.

Injectable forms are used for sinus bradycardia, asystole, organophosphorus poisoning, and anesthesia premedication.

• Sinus bradycardia (ACLS)
• Asystole / Pulseless Electrical Activity (ACLS)
• Organophosphorus poisoning
• Anesthesia premedication (antisialagogue)
• Bronchospasm (nebulization)
• Cycloplegia and mydriasis for eye examination
• Uveitis treatment
• Myopia progression control in children (0.01% solution)

Atropine is a competitive muscarinic receptor antagonist. It blocks acetylcholine at muscarinic receptors, reducing parasympathetic effects.

At low doses, it increases heart rate (by reducing vagal tone), reduces glandular secretions, and causes bronchodilation. At higher doses, CNS stimulation may occur.

In the eye, it causes mydriasis (pupil dilation) and cycloplegia (paralysis of accommodation) by blocking the sphincter pupillae and ciliary muscles.

Atropine competitively blocks muscarinic receptors (especially M1, M2, M3), preventing acetylcholine binding.

Cardiac: Reduces vagal tone, increases heart rate, improves AV conduction.
Glands: Reduces salivary, sweat, and bronchial secretions.
Eye: Mydriasis (pupil dilation) and cycloplegia (accommodation paralysis).
Myopia control: Acts on M1, M3, M4 receptors on scleral fibroblasts, causing scleral remodeling and reduced axial elongation.

Injection (IV/IM/SC):

• Anesthesia premedication: 0.4-0.6 mg, 30-60 min before anesthesia; repeat q4-6hr PRN
• Sinus bradycardia (ACLS): 0.5-1 mg or 0.04 mg/kg IV q5min; max 3 mg
• Asystole/PEA (ACLS): 1 mg IV q3-5min; up to 0.04 mg/kg
• Organophosphorus poisoning: 2 mg IV/IM, q10-30min until muscarinic effects resolve; maintain atropinization for at least 2 days
• Bronchospasm (nebulization): 0.025 mg/kg (max 2.5 mg/dose) in 2.5 mL NS, q6-8hr

Eye Drops (0.01% & 1%):

• Uveitis (1%): 1 drop three times daily
• Refraction (1%): 1 drop twice daily for 1-2 days before exam, and 1 hour before exam
• Myopia control (0.01%): 1 drop at night in each eye; continue for at least 2 years

Injection: Administered by healthcare professionals via IV/IM/SC.

Eye Drops: Apply pressure over lacrimal duct for 1 minute after instillation. Do not touch dropper tip. Do not use after 1 month of opening.

Injection: Not applicable (hospital administration).

Eye Drops: Apply as soon as remembered. Skip if near next dose.

Common (Eye Drops):

• Blurred vision
• Photophobia
• Local irritation
• Follicular conjunctivitis
• Vascular congestion, edema, exudate
• Contact dermatitis, eczematous dermatitis

Common (Injection/Systemic):

• Dry mouth
• Dysphagia
• Constipation
• Flushing and dry skin
• Tachycardia, palpitations, arrhythmias
• Mydriasis, photophobia, cycloplegia
• Raised intraocular pressure

Toxic doses: Tachycardia, hyperpyrexia, restlessness, confusion, excitement, hallucinations, delirium, circulatory failure, respiratory depression.

Serious Precautions:

• Contraindicated in angle-closure glaucoma [citation:4]
• Total dose should not exceed 0.03-0.04 mg/kg in patients with coronary artery disease [citation:9]
• May cause viscid plugs in chronic lung disease
• May cause complete urinary retention in prostatic hypertrophy
• May convert partial pyloric stenosis to complete obstruction
• Extreme caution in Down's syndrome, spastic paralysis, or brain damage [citation:4]
• Caution in pregnancy and lactation

• Angle-closure glaucoma or suspected angle-closure glaucoma [citation:4]
• Hypersensitivity to atropine or any component
• Prostatic hypertrophy (caution)
• Pyloric stenosis (caution)

• Anticholinergics: Additive effects (dry mouth, constipation, palpitations)
• Antiglaucoma agents: Opposing effects
• Potassium supplements / Potassium citrate: Risk of GI ulceration
• Carbachol, Physostigmine, Pilocarpine: Atropine blocks their effects
• CNS medications: Central effects may be altered

No specific food restrictions.

[CONSULT YOUR DOCTOR] Atropine may be systemically absorbed after ocular administration; however, significant fetal effects have not been reported. Use with caution during pregnancy. [citation:4]

[CONSULT YOUR DOCTOR] Systemically absorbed atropine is distributed into breast milk in very small amounts. May cause adverse effects (rapid pulse, fever, dry skin) in nursing infants. [citation:4]

Eye Drops: Do not use in children under 4 years of age [citation:4]. 0.01% atropine is effective for myopia control in children aged 4-14 years [citation:2][citation:5].

Injection: Pediatric dosing is weight-based.

Caution required in elderly patients due to risk of prostatic hypertrophy, glaucoma, and constipation.

No dose adjustment needed in renal impairment (hepatic metabolism and renal excretion).

Caution required in hepatic impairment (metabolized in liver).

Symptoms: Headache, fast heartbeat, dry mouth and skin, unusual drowsiness, flushing. [citation:4]

Management: Flush eye with water and seek emergency medical attention.

Eye Drops: Store below 30°C, in a dry place, away from light. Do not use after 1 month of opening. [citation:4]

Injection: Store as per manufacturer's instructions.

Atropine Sulphate (C₁₇H₂₃NO₃·H₂SO₄·H₂O)