Skeletal muscle relaxation
Unlike depolarising neuromuscular blocking agents, such as suxamethonium, Vecuronium bromide does not cause muscle fasciculations.
Within the clinical dosage range, Vecuronium bromide exerts neither vagolytic nor ganglion blocking activity.
The following agents have been shown to influence the magnitude and/or duration of action of non-depolarizing neuromuscular blocking agents:
Effect of Other Agents on Vecuronium:
Increased Effect:
- Halogenated volatile anaesthetics potentiate the neuromuscular block of Vecuronium. The effect only becomes apparent with maintenance dosing (see also Dosage and Administration). Reversal of the block with anticholinesterase inhibitors could also be inhibited.
- After intubation with suxamethonium
- Long-term concomitant use of corticosteroids and Vecuronium in the ICU may result in prolonged duration of neuromuscular block or myopathy.
Other medicines:
- antibiotics: aminoglycoside, lincosamide and polypeptide antibiotics, acylaminopenicillin antibiotics,
- diuretics, quinidine, magnesium salts, calcium channel blocking agents, lithium salts, cimetidine, lidocaine and acute administration of phenytoin or β-blocking agents
- Recurarization has been reported after post-operative administration of: aminoglycoside, lincosamide, polypeptide and acylamino-penicillin antibiotics, quinidine and magnesium salts
Decreased Effect (possible higher dose requirements):
- prior chronic administration of phenytoin or carbamazepine
- Variable Effect
- Administration of other non-depolarizing neuromuscular blocking agents in combination with Vecuronium may produce attenuation or potentiation of the neuromuscular block, depending on the order of administration and the neuromuscular blocking agent used.
- Suxamethonium given after the administration of Vecuronium may produce potentiation or attenuation of the neuromuscular blocking effect of Vecuronium.
Effect of Vecuronium on other agents:
Effect of Vecuronium on lidocaine: Vecuronium combined with lidocaine may result in a quicker onset of action of lidocaine.
Caesarean section: Studies with Vecuronium, administered in doses up to 0.1mg/kg, have shown its safety for use in caesarean section. In caesarean section the dose should not exceed 0.1mg/kg. In several clinical studies Vecuronium did not affect Apgar score, foetal muscle tonus or cardiorespiratory adaptation. From umbilical cord blood sampling it is apparent that only very little placental transfer of Vecuronium occurs which did not lead to the observation of any clinical adverse effect in the newborn.
Reversal of a Vecuronium induced neuromuscular block may be inhibited or unsatisfactory in patients receiving magnesium sulphate for toxaemia of pregnancy because magnesium salts enhance neuromuscular block.Therefore, in patients receiving magnesium sulphate, the dosage of Vecuronium should be reduced and be carefully titrated to twitch response.
Lactation: There are no human data on the use of Vecuronium during lactation. Vecuronium should be given to lactating women only when the attending physician decides that the benefits outweigh the risks.
As with other neuromuscular blocking agents, residual curarization has been reported for Vecuronium. In order to prevent complications resulting from residual curarization, it is recommended to extubate only after the patient has recovered sufficiently from neuromuscular block. Other factors which could cause residual curarization after extubation in the post-operative phase (such as medicine interactions or patient condition) should also be considered. If not used as part of standard clinical practice, the use of a reversal agent should be considered, especially in those cases where residual curarization is more likely to occur.
Anaphylactic reactions can occur following the administration of neuromuscular blocking agents. Precautions for treating such reactions should always be taken. Particularly in the case of previous anaphylactic reactions to muscle relaxants, special precautions should be taken since allergic cross-reactivity to muscle relaxants has been reported.
Since Vecuronium has no cardiovascular effects within the clinical dosage range, it does not attenuate bradycardia that may occur due to the use of some types of anaesthetics and opiates or due to vagal reflexes during surgery. Therefore, reassessment of the use and/or dosage of vagolytic medicines such as atropine for premedication or at induction of anaesthesia, may be of value for surgical procedures during which vagal reactions are more likely to occur (e.g. surgical procedures where anaesthetic medicines with known vagal stimulatory effects are used, ophthalmic, abdominal or anorectal surgery, etc).
In general, following long term use of neuromuscular blocking agents in the ICU, prolonged paralysis and/or skeletal muscle weakness has been noted. In order to help preclude possible prolongation of neuromuscular block and/or overdosage it is strongly recommended that neuromuscular transmission is monitored throughout the use of muscle relaxants. In addition, patients should receive adequate analgesia and sedation. Furthermore, muscle relaxants should be titrated to effect in the individual patients by or under supervision of experienced clinicians who are familiar with their actions and with appropriate neuromuscular monitoring techniques. Myopathy after long term administration of non-depolarizing neuromuscular blocking agents in the ICU in combination with corticosteroid therapy has been reported frequently. Therefore, for patients receiving both neuromuscular blocking agents and corticosteroids, the period of use of the neuromuscular blocking agent should be limited as much as possible.
When administration of an acetylcholinesterase-inhibiting agent fails to reverse the neuromuscular effects of Vecuronium, ventilation must be continued until spontaneous breathing is restored. Repeated dosage of an acetylcholinesterase inhibitor can be dangerous.