Local anaesthetic safety
Calculate safe use for the individual, aspirate where appropriate and recognise toxicity or vasoconstrictor-related effects.
Understand
Local anaesthetic effectiveness and safety depend on agent, concentration, vasoconstrictor, injection technique and the individual. Anxiety-related symptoms can resemble drug reactions.
Assess
Check weight where relevant, medical history, previous reactions and planned total dose; use aspiration and incremental delivery according to technique.
Apply
Recognise early toxicity signs and stop injection promptly if suspected. Document the agent, dose and site, and avoid labelling every palpitating patient “allergic”.
Key distinctions
Maximum local anaesthetic dose is patient- and product-specific and should be calculated from the formulation and body weight when relevant. Intravascular injection or rapid absorption may cause early neurological and cardiovascular symptoms. Palpitations after vasoconstrictor, anxiety and genuine allergy have different implications. Record details so future clinicians do not inherit a vague and potentially misleading “LA allergy” label.
Think through a case
A patient feels palpitations and shaking after an injection containing vasoconstrictor. Assess the event before recording a lifelong allergy label.
The distinction to remember
Do not ignore cumulative local anaesthetic dose or inject under pressure into a vessel.
Test your recall
Why ask about prior reactions to local anaesthetic?
Show answer
To distinguish allergy, toxicity, anxiety and other events.