Adults: Dosage
The recommended initial dose of Vecuronium is 0.08 to 0.10 mg per kg body weight, given as an intravenous bolus injection. This dose can be expected to produce good or excellent conditions for non emergency intubation within 2.5 to 3.0 minutes after injection. In caesarean section and neonatal surgery the dose should not exceed 0.1 mg/kg.
Like other neuromuscular blocking agents, Vecuronium Bromide should only be given by, or under the supervision of, experienced clinicians who are familiar with the action and use of these agents, and the dose should be individualized for each patient. Accordingly, adjustments should be made by giving smaller maintenance doses at less frequent intervals, or by using lower infusion rates, during long lasting procedures of more than one hour under inhalational anaesthesia.
In adult patients the following dosage recommendations may serve as a general guideline for tracheal intubation and muscle relaxation in surgical procedures of short to long duration.
Tracheal intubation. The standard intubating dose during routine anaesthesia is 0.08 to 0.1 mg Vecuronium Bromide per kg body weight, after which adequate intubation conditions are established within 90 to 120 seconds in nearly all patients.
Dosage for surgical procedures after intubation with suxamethonium. If suxamethonium is used for intubation, the administration of Vecuronium should be delayed until the patient has clinically recovered from the neuromuscular block caused by suxamethonium. The recommended dose is 0.03 to 0.05 mg Vecuronium Bromide per kg body weight.
Maintenance dosing. The recommended maintenance dose is 0.02 to 0.03 mg Vecuronium Bromide per kg body weight. These maintenance doses are best given when twitch height has recovered to 25 percent of the control twitch height.
Dose requirements for continuous infusion. If Vecuronium is given by continuous infusion, it is recommended to give a loading dose of 0.08 to 0.1 mg Vecuronium Bromide per kg body weight first, and to start the infusion once the neuromuscular block begins to recover. The infusion rate should be adjusted to maintain the twitch response at 10 percent of the control twitch height, or to maintain 1 to 2 responses to train of four stimulation. In adults, the infusion rate needed to maintain neuromuscular block at this level ranges from 0.8 to 1.4 microgram Vecuronium Bromide per kg per minute. Repeat monitoring of the neuromuscular block is recommended, since infusion rate requirements vary from patient to patient and with the anaesthetic method used.
Dosing in elderly patients. The same intubation and maintenance doses used in younger adults, 0.08 to 0.1 mg/kg and 0.02 to 0.03 mg/kg respectively, can be used. The onset time in elderly patients is similar to that in younger adults.
Dosing in paediatric patients. In neonates up to 4 weeks and children up to 4 months, an initial test dose of 0.01 to 0.02 mg/kg is recommended, followed by incremental doses until 90 to 95 percent depression of the twitch response is achieved. In neonatal surgery the dose should not exceed 0.1 mg/kg. In children from 5 months to 10 years, the dose is 0.08 to 0.1 mg/kg, though children under 12 months tend to have a more rapid onset and may not need the full intubating dose. Maintenance in this age group is 0.02 to 0.03 mg/kg, adjusted according to response. Because the duration of action is shorter in children, maintenance doses are needed more frequently.
Dosing in overweight and obese patients. Doses in overweight or obese patients should be reduced, taking ideal body weight into account. Initial doses ranging from 0.15 mg up to 0.30 mg Vecuronium Bromide per kg body weight have been given during surgery under both halothane and neurolept anaesthesia.