ARTACIL INJ 25MG

Indications

• Induction of muscle relaxation during surgical procedures
• Facilitation of mechanical ventilation
• Adjunct in anaesthesia

Dosage

Children: Refer to the BNF for Children for specific dosing guidance.

Adults: The usual initial dose is 0.5 mg/kg for intubation, with maintenance doses of 0.1-0.2 mg/kg as needed based on clinical response.

Mechanism of action

Atracurium works by competitively antagonizing the action of acetylcholine at the neuromuscular junction. It binds to nicotinic receptors on the motor end plate, preventing acetylcholine from attaching and initiating muscle contraction. This results in muscle paralysis that is reversible with the administration of acetylcholinesterase inhibitors.

Pharmacodynamics

The onset of action for atracurium is rapid, generally occurring within 2-3 minutes of intravenous administration. The duration of neuromuscular block is dose-dependent, typically lasting between 20-40 minutes. Recovery occurs as atracurium is metabolized and eliminated from the body, with spontaneous recovery generally observed after the drug has been cleared from the neuromuscular junction.

Pharmacokinetics

Atracurium is administered intravenously and is characterized by a volume of distribution of approximately 0.2-0.5 L/kg. It is metabolized through a process called ester hydrolysis and also via a unique reaction known as the 'Hofmann elimination,' which occurs at physiological pH and temperature. The clearance rate is around 0.1-0.3 L/min/kg, and the elimination half-life is typically 20-30 minutes. Atracurium does not accumulate in patients with renal or hepatic impairment due to its unique metabolic pathways.

Contra-indications

• Hypersensitivity to atracurium or any component of the formulation
• Myasthenia gravis

Adverse effects

• Hypotension
• Respiratory depression
• Bradycardia
• Anaphylactic reactions
• Prolonged neuromuscular block
• Histamine release causing flushing, tachycardia, and bronchospasm

Interactions

• Aminoglycoside antibiotics may potentiate neuromuscular block
• Calcium channel blockers may increase neuromuscular blockade
• Volatile anesthetics may enhance neuromuscular block
• Magnesium salts may exacerbate neuromuscular blockade

Precautions

• Use with caution in patients with cardiovascular disease
• Monitor patients for prolonged neuromuscular block
• Careful use in patients with renal or hepatic impairment

Pregnancy

Atracurium is classified as pregnancy category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

There are no data on the excretion of atracurium in human milk. Caution should be exercised when administering to a nursing mother.

Storage

Store in a cool, dry place away from light. Do not freeze.

Formulations

• Injection solution (usually in vials for intravenous use)

Indications

• Neuromuscular blockade during surgery
• Neuromuscular blockade in intensive care

Dosage

Children: For neonates, initially 300–500 micrograms/kg, followed by 100–200 micrograms/kg every 20 minutes as required. For children (2–11 years), initially 150 micrograms/kg, followed by 80–100 micrograms/kg every 10 minutes if not for intubation.

Adults: Initially by intravenous injection, 0.5–1 mg/kg, adjusted according to response. For maintenance, doses of 0.1–0.2 mg/kg can be given as needed.

Mechanism of action

Atracurium works by competitively inhibiting the action of acetylcholine at the neuromuscular junction, preventing muscle contraction.

Pharmacodynamics

Atracurium produces a dose-dependent neuromuscular blockade, with effects that can be reversed by acetylcholinesterase inhibitors. Its duration of action is intermediate, making it suitable for various surgical procedures.

Pharmacokinetics

Atracurium is metabolised via non-specific plasma esterases and tissue esterases, which allows it to be eliminated without reliance on renal or hepatic function. Its onset of action is rapid, and the effects can be reversed by spontaneous recovery or with reversal agents.

Adverse effects

• Hypotension
• Bradycardia
• Flushing
• Bronchospasm

Interactions

• Neuromuscular blocking drugs (non-depolarising) may interact
• Caution in patients with cardiovascular disease due to potential hypotension

Precautions

• Use caution in patients with cardiovascular disease or sensitivity to hypotension
• Dose adjustments may be necessary in neonates and patients with extremes of body weight

Pregnancy

Refer to specific guidelines; safety not established.

Breast-feeding

Refer to specific guidelines; safety not established.

Storage

Store in a cool, dry place away from light. Protect from freezing.

Formulations

• 25mg/2.5ml solution for injection ampoules
• 250mg/25ml solution for injection vials