Page 107 - pharma 1 theoretical updated MNU_Neat

Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

Factors predisposing to digoxin toxicity

Electrolytic disturbances

➢ Hypokalemia can precipitate serious arrhythmia (make cardiac muscle more sensitive
to digoxin toxicity)
 Reduction of serum potassium levels is most frequently observed in patients receiving

thiazide or loop diuretics, which can usually be prevented by use of a potassium-
sparing diuretic or supplementation with potassium chloride.
➢ Hypercalcemia and hypomagnesaemia ➔ Mg important for relaxation also

predispose to digoxin toxicity.
Drugs

➢ Quinidine(antiarrhythmic) verapamil (CCB), and amiodarone (antiarrhythmic), ➔
digoxin intoxication, both by displacing digoxin from tissue protein-binding sites and

by competing with digoxin for renal excretion.
➢ digoxin plasma levels may increase by 70 to 100 percent ➔requiring dosage
reduction.
➢ Potassium- depleting diuretics, corticosteroids → ↑ digoxin toxicity.

Diseases

➢ Hypothyroidism (myocardial contractility), hypoxia, renal failure, and myocarditis
➔ are also predisposing factors to digoxin toxicity.

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