Drug of choice for lignocaine toxicity ?
Ans. is 'b' i.e., Phenobarbitone Lignocaine toxicity Lignocaine toxicity occurs with unintended intravascular administration or with administration of excessive dose Toxicity may be observed at 6 ug/ml, but more commonly occur once levels exceed 10 tg/ml. Clinical manifestations 1. CNS manifestations These are the most common manifestations of toxicity. CNS lidocaine toxicity is biphasic Earlier manifestations-are due to CNS excitation e.g. convulsions Subsequent manifestations -are due to CNS depression drowsiness, disorientation, respiratory depression. The cause of biphasic response is Local anaesthetic action first blocks inhibitary CNS pathways-resulting in stimulation Eventually blocks both inhibitory and excitatory pathways- overall CNS depression 2. Cardiovascular manifestations These occur at higher serum concentrations There may be cardiac depression, hypotension, coma, respiratory arrest. Note: lignocaine can precipitate malignant hypehermia Management of toxicity If lignocaine toxicity is suspected, stop the injection immediately. Ensure adequate oxygenation, whether by face mask or by intubation. Anticonvulsants such as benzodiazepines and barbiturates are the drug of choice for seizure control. Succinykholine is sometimes also used to terminate the neuromuscular effects of seizures. If CVS symptoms occur (cardiac depression and hypotension), IVfluid and vasopressor agents may be required. If metabolic acidosis develops, use of sodium bicarbonate can be considered, although, as in other instances of acute metabolic acidosis, this is controversial
Phenytoin
Phenobarbitone
Beta-blockers
Amiodarone