PHARMACARE ATROPINE SULPHATE

Indications

• Bradycardia
• Pre-anesthetic medication to reduce salivary secretions
• Antidote for organophosphate poisoning
• Pupil dilation for ophthalmic examinations

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations for children.

Adults: Refer to the BNF for specific dosing recommendations based on the condition being treated.

Mechanism of action

Atropine competes with acetylcholine for binding to muscarinic receptors in the parasympathetic nervous system. By blocking these receptors, atropine inhibits the actions of acetylcholine, leading to effects such as increased heart rate, decreased gastrointestinal motility, and reduced secretions from glands such as salivary and sweat glands.

Pharmacodynamics

Atropine exhibits dose-dependent effects, with low doses primarily causing inhibition of secretions and higher doses leading to increased heart rate and decreased gastrointestinal motility. Its antimuscarinic properties can also lead to dilation of the pupils (mydriasis) and paralysis of accommodation (cycloplegia). These effects are useful in various clinical situations, such as managing bradycardia or in ophthalmic examinations.

Pharmacokinetics

Atropine is well-absorbed after administration and has a rapid onset of action. It is distributed widely throughout the body, including the central nervous system. The drug is metabolized primarily in the liver, and its elimination half-life varies, typically ranging from 2 to 4 hours. Atropine is excreted in urine, both as unchanged drug and as metabolites.

Contra-indications

• Hypersensitivity to atropine or any of its components
• Angle-closure glaucoma
• Myasthenia gravis
• Obstructive gastrointestinal disease
• Severe ulcerative colitis
• Tachycardia due to thyrotoxicosis

Adverse effects

• Dry mouth
• Blurred vision
• Increased heart rate
• Urinary retention
• Constipation
• Dizziness
• Confusion
• Hallucinations

Interactions

• clozapine+atropine: Unknown (additive effect)
• antipsychotics, second generation+atropine: Unknown (additive effect)

Precautions

• Use with caution in patients with cardiovascular disease
• Use with caution in elderly patients due to increased sensitivity
• Caution in patients with prostatic hypertrophy

Pregnancy

Atropine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is classified as a Category C drug.

Breast-feeding

Atropine is excreted in breast milk. Caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place, protected from light. Keep out of reach of children.

Formulations

• Atropine sulfate injection
• Atropine tablets

Indications

• Bradycardia
• Premedication for general anesthesia
• Management of organophosphate poisoning

Dosage

Children: For bradycardia, 20 micrograms/kg IV every 5-10 minutes (max. per dose 2 mg) until adequate response.

Adults: For bradycardia, 0.5 to 1 mg IV, may repeat every 3-5 minutes as needed (max total dose 3 mg). For premedication, 0.5 mg IV 30-60 minutes before anesthesia.

Mechanism of action

Atropine sulfate works by blocking the action of acetylcholine at muscarinic receptors, leading to decreased vagal tone and increased heart rate. It also reduces secretions from glands in the respiratory tract and gastrointestinal tract.

Pharmacodynamics

Atropine has a rapid onset of action, particularly when administered intravenously. Its effects on heart rate can be noted within minutes, while its anti-secretory effects can last for several hours. The drug's half-life varies, but its effects can be prolonged due to its ability to cross the blood-brain barrier.

Pharmacokinetics

Atropine sulfate is well absorbed after parenteral administration. It is metabolized in the liver and excreted primarily via the kidneys. The duration of action typically ranges from 1 to 4 hours, depending on the dose and route of administration.

Adverse effects

• Dizziness
• Photophobia
• Skin reactions
• Tachycardia

Interactions

• Caution with beta-blockers
• May interact with other antimuscarinics

Precautions

• Children under 3 months due to the possible association between cycloplegia and the development of amblyopia
• Monitor for effects on driving and skilled tasks due to increased risk of blurred vision

Pregnancy

Manufacturer advises avoid unless potential benefit outweighs risk-no information available.

Breast-feeding

Manufacturer advises avoid-limited information available.

Storage

Store at room temperature, away from light and moisture.

Formulations

• Eye drops
• Eye ointment