Overdose : מינון יתר

4.9   Overdose
Undesirable effects (showing an abnormally high concentration of local anaesthetic in the blood) may appear either immediately, caused by accidential intravascular injection or abnormal absorption conditions, e.g. in inflamed or intensive vascularised tissue, or later, caused by true overdose following an injection of excessive quantity of anaesthetic solution, and manifest themselves as central nervous and/or vascular symptoms.
Symptoms caused by the local anaesthetic ingredient articaine:
Milder central nervous symptoms involve metallic taste, tinnitus, dizziness, nausea, vomiting, restlessness, anxiety, initial increase in respiratory rate.
More severe symptoms are drowsiness, confusion, tremor, muscular twitching, tonic-clonic seizures, coma and respiratory paralysis.
Severe cardiovascular episodes are seen in the form of a drop in blood pressure, cardiac impulse conduction disorders, bradycardia, cardiovascular arrest.
Symptoms caused by epinephrine as a vasoconstrictor:
Cardiovascular symptoms such as heat sensation, sweating, heart racing, migrainelike headache, blood pressure increase, angina pectoris disorders, tachycardias, tachyarrhythmias, cardiovascular arrest and acute oedematous thyroid swelling.
Interferences in the clinical picture can result from the simultaneous occurrence of various complications and side effects.
Therapy
If adverse reaction arise the application of the local anaesthetic has to be stopped.
General basic measures:
Diagnostics (respiration, circulation, consciousness), maintenance/restoration of the vital functions of respiration and circulation, oxygen administration, intravenous access.
Special measures:
Hypertension: Elevation of the upper body, if necessary sublingual nifedipine.
Convulsions: Protect patients from concomitant injuries, if necessary benzodiazepins (e.g. diazepam iv).
Hypotension: Horizontal position, if necessary intravascular infusion of a whole electrolyte solution, vasopressors (e.g. etilefrine iv).
Bradycardia: Atropine iv.
Anaphylactic shock: Contact emergency physician, in the meantime shock positioning, generous infusion of a whole electrolyte solution, if necessary epinephrine iv, cortisone iv.
Cardiovascular arrest: Immediate cardiopulmonary resuscitation, contact emergency physician.