L11: Digitalis & Theophylline Flashcards
Source of Digitalis
The roots, leaves and seeds of “Digitalis Purpurea” contain several poisonous glycosides.
Toxic Action of Digitalis
Risk factors for Digitalis Toxicity
- Age
- Renal functions
- Electrolyte indisturbances
- Drug Interactions
- Natural products
Age Risk Factors for Digotalis Toxicity
Adyanced age (>80 y) is associated with increased morbidity and mortality.
Renal Function Risk Factors for Digotalis Toxicity
Deteriorating renal function, dehydration, electrolyte disturbances or drug interactions, usually precipitates chronic toxicity.
Electrolyte Disturbances Risk Factors for Digotalis Toxicity
Drug Interactions Risk Factors for Digotalis Toxicity
- Drug interactions are one of the most common causes of digoxin Toxicity
(e.g., Beta-blockers, Calcium channel blockers, Quinidine, loop diuretics)
Natural Products Risk Factors for Digotalis Toxicity
Natural licorice should be avoided as it causes
- Sodium and water retention
- Increases potassium loss.
CP of Digitalis Toxicity
what causes yellow-green visual changes with digitalis toxicity?
due toxic effects on retinal con than rod cell.
Types of Digitalis Toxicity
- Acute overdose toxicity.
- Acute versus chronic use toxicity (more common).
Investigations in Digitalis Toxicity
TTT of Digitalis Toxicity
- Emergency TTT & Supportive
- Decontamination
- Antidote
- Enhanced Elimination
Emergency TTT of Digitalis Toxicity
- ABC and assist ventilation if necessary.
- Continuous cardiac monitoring for at least 12-24 hours after significant ingestion due to delayed tissue distribution
Continuous cardiac monitoring for at least 12-24 hours after significant ingestion of digitalis due to ……..
due to delayed tissue distribution
Aspects of Emergency TTT in Digitalis Toxicity
- Bradycardia or Heart block
- Ventricular Arrhythmias
- Hyperkalemia
- Hypokalemia
Emergenct TTT of bradycardia & Heart Block in Digitalis Toxicity
- Give atropine 0.5-2mg l.V.
- Temporary transvenous cardiac pacemaker may be needed
Emergency TTT of Ventricular Arrythmia in Digitalis Toxicity
- Fab is the preferred treatment for life-threatening arrhythmias.
- Lidocaine is the antiarrhythmic drug of choice.
Emergency TTT of hyperkalemia in Digitalis Toxicity
(VIP)
when does hyperkalemia of Digitalis Toxicity need TTT?
Needs treatment especially if associated with ECG changes
what to do in a case of Hyperkalemia due to digitalis if no FAB is available?
Give triad of
- Sodium bicarbonate (1 mEq/kg)
- Glucose (0.5 g/kg IV)
- Given simultaneously with Insulin (0.1 U/kg IV)
or Sodium Polystyrene Sulfonate (Kayexalate, 0.5 g/kg PO)
Types of TTT of Hyperkalemia associated with Digitalis Toxicity
Moderate elevation of serum k (>5.5 mEq/L):
- Fab Fragment: It rapidly reverses it
Progressive elevation of serum k (k > 6-7 mEq/ L):
- Bi-Carbonate/Glucose/Insulin
why shouldn’t calcium be used in hyperkalemia of Digitalis Toxicity?
may worsen ventricular arrhythmias.