Indirin Overdosage

Toxicity: Individual response varies greatly, death in adult has followed ingestion of about 2 g, and ingestion of more than 40 mg may cause serious problem in children.
Symptoms: Cardiac: Bradycardia, hypotension, pulmonary edema, syncope and cardiogenic shock may develop. Conduction abnormalities such as first or second degree AV block may occur. Rarely arrhythmias may occur. Development of cardiovascular complications is more likely if other cardioactive drugs, especially calcium channel blockers, digoxin, cyclic antidepressants or neuroleptics have also been ingested. The elderly and those with underlying ischaemic heart disease are risk of developing severe cardiovascular compromise.
CNS: Drowsiness, confusion, seizures, hallucinations, dilated pupils and in severe cases coma may occur. Neurological sign such as coma or absence of pupil reactivity are unreliable prognostic indicators during resuscitation.
Other features: bronchospasm, vomiting and occasionally CNS-mediated respiratory depression may occur. The concept of cardioselectivity is much less applicable in the overdose situation and systemic effects of beta-blockade include bronchospasm and cyanosis. Particularly in those with pre-existing airways disease. Hypoglycemia and hypocalcemia are rare and occasionally generalized spasm may also be present.
Treatments: In cases of overdose or extreme falls in the heart rate or blood pressure, treatment with propranolol must be stopped. In addition to primary poison elimination measures, vital parameters must be monitored and corrected accordingly in intensive care. In case of cardiac arrest, the resuscitation of several hours may be indicated. This should include general symptomatic and supportive measures including a clear airway and monitoring of vital signs until stable. Consider activated charcoal (50 g for adults, 1 g/kg for children) if an adult presents within 1 hour of ingestion of more than a therapeutic dose or a child for any amount. Atropine should be administered before gastric lavage, when required, as there is a risk of vagal stimulation. Alternatively, consider gastric lavage in adults within 1 hour of a potentially life-threatening overdose. Excessive bradycardia may respond to large dose of atropine (3 mg intravenously for an adult and 0.04 mg/kg for a child) and/or a cardiac pacemaker.
For severe hypotension, heart failure, or cardiogenic shock in adults, a 5-10 mg IV bolus of glucagon (50-150 micrograms/kg in a child) should be administered over 10 minutes to reduce the likelihood of vomiting, followed by an infusion of 1-5 mg/hour (50 micrograms/kg/hour), titrated to clinical response. If glucagon is not available or if there is severe bradycardia and hypotension, which is not improved by glucagon, the beta blocking effect can be counteracted by slow intravenous administration of isoprenaline hydrochloride, dopamine or noradrenaline. In severe hypotension additional inotropic support may be necessary with a beta agonist such as dobutamine 2.5 - 40 micrograms/kg/min (adults and children). It is likely that these doses would be inadequate to reverse the cardiac effects of beta blockade if a large overdose has been taken. The dose of dobutamine should therefore be increased if necessary to achieve the required response according to the clinical condition of the patient.
Nebulised salbutamol 2.5-5 mg should be given for bronchospasm. Intravenous aminophylline may be of benefit in severe case (5 mg/kg over 30 mins followed by and infusion of 0.5-1 mg/kg/hour). Do not give the initial loading dose of 5 mg/kg if the patients is taking oral theophylline or aminophylline. Cardiac pacing may also be effective at increasing heart rate but does not always correct hypotension secondary to myocardial depression.
In cases of generalized spasm, a slow intravenous dose of diazepam may be used (0.1-0.3 mg/kg body weight).