1. Clinical Overview
Atracurium besylate is a non-depolarizing, intermediate-duration, benzylisoquinolinium neuromuscular blocking agent (NMBA). It is a bis-cationic compound that acts as a competitive antagonist at the nicotinic acetylcholine receptors of the neuromuscular junction. Its unique feature is its metabolism via Hofmann elimination (a non-enzymatic, pH- and temperature-dependent process) and ester hydrolysis, making it largely independent of hepatic and renal function. It is widely used in Indian operating theatres for endotracheal intubation and as an adjunct to general anesthesia to provide skeletal muscle relaxation during surgery.
| Onset | Duration | Bioavailability |
|---|---|---|
| 2-3 minutes | 20-35 minutes | 100% (Intravenous administration only) |
2. Mechanism of Action
Atracurium is a competitive antagonist at the post-synaptic nicotinic acetylcholine receptors (Nm) at the skeletal muscle neuromuscular junction. It binds to the alpha subunits of the receptor, preventing acetylcholine from binding and initiating depolarization of the motor endplate. This results in flaccid paralysis of skeletal muscles.
3. Indications & Uses
- Adjunct to general anesthesia to facilitate endotracheal intubation.
- Provision of skeletal muscle relaxation during surgical procedures.
4. Dosage & Administration
Adult Dosage: Intubation: 0.4 to 0.5 mg/kg IV bolus. Maintenance: 0.08 to 0.1 mg/kg IV bolus as required, or a continuous infusion of 0.3 to 0.6 mg/kg/hr (5-10 mcg/kg/min). Dose must be individualized based on clinical response and use of a peripheral nerve stimulator is recommended.
Administration: For IV use only. Must be administered by or under the direct supervision of an anesthesiologist. Bolus dose should be given over 30-60 seconds to minimize histamine release. For continuous infusion, dilute in a compatible IV solution (e.g., 0.9% NaCl, 5% Dextrose). Do not mix with alkaline solutions (e.g., thiopentone) in the same syringe or IV line. Use a nerve stimulator to monitor depth of blockade and guide dosing.
5. Side Effects
Common side effects may include:
- Transient hypotension
- Flushing/erythema of the skin, especially face, neck, and chest
- Tachycardia
- Injection site reactions
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Inhalational Anesthetics (Isoflurane, Sevoflurane, Desflurane) | Potentiate neuromuscular blockade, reducing atracurium dose requirement by 15-50%. | Major |
| Aminoglycosides (Gentamicin, Amikacin) | Potentiate neuromuscular blockade, may cause prolonged apnea. | Major |
| Magnesium Sulfate | Potentiates neuromuscular blockade. | Major |
| Succinylcholine | Prior use may enhance the depth and duration of atracurium blockade. | Moderate |
| Calcium Channel Blockers (Verapamil) | May enhance neuromuscular blockade. | Moderate |
| Corticosteroids (chronic use) | May cause resistance to non-depolarizing NMBAs. | Moderate |
| Phenytoin, Carbamazepine | May cause resistance, requiring higher doses of atracurium. | Moderate |
7. Patient Counselling
- Do inform your anesthesiologist about all allergies, especially to medications.
- Do disclose any history of neurological or muscular disorders (e.g., myasthenia gravis).
- Do inform about any kidney or liver problems.
- Do not drive or operate heavy machinery for at least 24 hours after surgery or until cleared by your doctor.
8. Toxicology & Storage
Overdose: Prolonged neuromuscular blockade leading to apnea, respiratory insufficiency or arrest, cardiovascular collapse (from histamine release).
Storage: Store at 2°C to 8°C (refrigerate). Do not freeze. Protect from light. The diluted solution for infusion is stable at room temperature for 24 hours. The product is supplied in single-use vials/ampoules. Discard any unused portion.