Calcium channel blocker and beta blocker poisoning

T46.1

DESCRIPTION

Cardiovascular toxicity results in profound hypotension, bradycardia, decreased systemic vascular resistance and cardiogenic shock. Depressed level of consciousness and metabolic acidosis are consequent upon poor tissue perfusion. Hyperglycaemia and hypokalaemia may occur.

Patients who have co-ingested other cardiac medicines and those with pre-

existing cardiac disease are at increased risk of morbidity.

The treatment of suspected cardiogenic shock in calcium channel blocker and beta blocker poisoning follows similar therapeutic principles. The mainstay of treatment is high-dose insulin euglycaemia therapy and catecholamine infusions to improve inotropy and chronotropy.

LoEIII [44]

GENERAL MEASURES

Monitor vital signs, ECG and blood glucose.

Treat symptomatic patients in consultation with a specialist.

MEDICINE TREATMENT

  • Caution is advised for all decontamination procedures as they increase vagal tone and may exacerbate bradycardia.
  • Activated charcoal may be considered before the onset of symptoms.
  • Whole bowel irrigation can be considered for ingestion of modified-release preparations.

LoEIII [45]

Treat hypotension: I95.9 + (T46.1/X44.99/X64.99/Y14.99)

  • Sodium chloride, IV, 0.9%.

LoEIII [46]

If hypotension not effectively controlled add:

  • Calcium gluconate 10%, IV, 30–60 mL given over 15–30 minutes, with ECG monitoring.
    • This may be repeated a maximum of 4 times.

LoEIII [47]

Treat bradycardia: R00.1 + (T46.1/X44.99/X64.99/Y14.99)

  • Atropine, IV 0.5–1 mg every 2–3 minutes to a maximum of 3 mg.

LoEIII [48]

Use vasopressors as needed, e.g. adrenaline (epinephrine) infusion for persistent hypotension ( Cardiac arrest - cardiopulmonary resuscitation) or dobutamine for bradycardia (Cardiogenic shock).

REFERRAL

Refer for management with high dose insulin for resistant hypotension and bradycardia, in a high care or ICU setting.

If glucose <10 mmol/L:

Followed by:

  • Insulin, fast acting, IV, 1 unit/kg.
    • Followed by 0.5 unit/kg/hour.
    • Titrate dose up until hypotension is corrected, to maximum 10 units/kg/hour.

Monitor and correct potassium and glucose.

LoEIII [50]