OVERDOSAGE
— If overdosage occurs, nausea, vomiting, gastric hypotonicity,
and diarrhea would be expected without causing consequential toxicity.
Signs and
Symptoms
Intravenous administration of glucagon has been shown to
have positive inotropic and chronotropic effects. A transient increase in
both blood pressure and pulse rate may occur following the administration
of glucagon. Patients taking β-blockers might be expected to have a greater
increase in both pulse and blood pressure, an increase of which will be transient
because of glucagon's short half-life. The increase in blood pressure
and pulse rate may require therapy in patients with pheochromocytoma or coronary
artery disease.
When glucagon was given in
large doses to patients with cardiac disease, investigators reported a positive
inotropic effect. These investigators administered glucagon in doses of 0.5 to
16 mg/hour by continuous infusion for periods of 5 to 166 hours. Total doses
ranged from 25 to 996 mg, and a 21-month-old infant received approximately
8.25 mg in 165 hours. Side effects included nausea, vomiting, and decreasing
serum potassium concentration. Serum potassium concentration could be maintained
within normal limits with supplemental potassium.
The
intravenous median lethal dose for glucagon in mice and rats is approximately
300 mg/kg and 38.6 mg/kg, respectively.
Because
glucagon is a polypeptide, it would be rapidly destroyed in the gastrointestinal
tract if it were to be accidentally ingested.
— To obtain up-to-date information about the treatment of overdose,
a good resource is your certified Regional Poison Control Center. Telephone
numbers of certified poison control centers are listed in the. In managing overdosage, consider the possibility
of multiple drug overdoses, interaction among drugs, and unusual drug kinetics
in your patient.
Treatment
Physicians'
Desk Reference (PDR)
In view of the extremely short
half-life of glucagon and its prompt destruction and excretion, the treatment
of overdosage is symptomatic, primarily for nausea, vomiting, and possible
hypokalemia.
If the patient develops a dramatic
increase in blood pressure, 5 to 10 mg of phentolamine mesylate has been shown
to be effective in lowering blood pressure for the short time that control
would be needed.
Forced diuresis, peritoneal
dialysis, hemodialysis, or charcoal hemoperfusion have not been established
as beneficial for an overdose of glucagon; it is extremely unlikely that one
of these procedures would ever be indicated.
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